Windows Phone 8 (WP8) - Sending emails using personal domain names

[#1]

I have a Nokia 920 running Windows Phone 8 (actually 8.0.10328.0 - the most recent update available for this phone).
I have set up a PlusNet email account using "email + account" > "add an account" - initially using "other account" and when that didn't do what I wanted I tried "advanced setup".
With either option I've ended up with the same result - the phone is working perfectly and synchronising with PlusNet properly, so I can see all incoming emails perfectly, but any emails sent from the phone are displaying my PlusNet email address (i.e. format me@plusnetusername.plus.com) rather than the domain name ones I always use (i.e. format me@mydomainname.co.uk). I never use my PlusNet email address in its native form.
The problem is I cannot find any setting where I can add in the domain name email addresses I regularly use and no way of selecting them when replying to an email or writing a new one.
This ultimately makes the application useless since I can't send emails in the right format using my domain name email addresses.
Can anyone point to a solution please? Is there a setting I've missed which will make an option box appear when composing emails to select the relevant email address? I don't want to have to resort to always sending emails from my phone using the web browser and PlusNet's webmail site since it's not nearly as easy to use on a small screen.

[#2]

I've found a similar query on another forum (http://www.makeuseof.com/tag/everything-you-need-to-know-about-emails-windows-phone-8/) but no pertinent replies:
"Hi. One problem I have noted is that if you use Outlook.com on your WP8 and that is configured to receive emails from several different accounts and also has a number of aliases from which you can send emails, the latter do not appear on your WP8 device. In other words all my emails come tumbling in nicely into a number of outlook.com defined folders but when I reply I only have the default outlook.com email address as an account option, none of my aliases. Does anyone know of a way around this since you cannot reply to an email received by one account, using another. (not like you can in Outlook 2010)"

[#3]

From this http://www.windowsphone.com/en-gb/how-to/wp7/people/set-up-an-email-account it would appear that you need to specify your domain address when creating the email account and then use the plusnet details for the account username and password.
Try deleting the account on the phone and starting again

[#4]

(Written before trying out the previous response which I've just noticed.)
Having tried Googling using the word "alias" I've now found http://forums.wpcentral.com/windows-phone-8/198949-outlook-com-email-aliases.html
Does this mean I could get round the problem by setting up separate outlook.com accounts for each domain name email address (there's current two I use a lot) and by linking those accounts to my PlusNet inbox, and setting the default address for each of those as my domain name email address, I could then send emails and responses via outlook.com?
Problem is I've tried linking my PlusNet and Outlook inboxes together and - yes - while that now means that when I hit the "new email" button I get a choice of accounts to send from, when replying to an email, there's no option to change the account. So only a partial soultion, and not much help since I'm more likely to be replying to an incoming email than composing a new one. I suppose I could cut'n'paste from the incoming email into a new outgoing email but surely there must be a "proper" solution to this problem...

[#5]

Quote from: MisterW

From this http://www.windowsphone.com/en-gb/how-to/wp7/people/set-up-an-email-account it would appear that you need to specify your domain address when creating the email account and then use the plusnet details for the account username and password. Try deleting the account on the phone and starting again

Thanks - I'm trying this but adding an additional account rather than deleting as suggested. It's synchronising at present.

[#6]

Right - thanks for that. That's solved the problem for sending new emails - and incidental sharing pictures, etc - since the correct email address now appears in the listing.
And having now deleted the original PlusNet account, I find response emails going out using my principal email address. However even if I add the other domain name email address I use regularly I still can't see I'm going to be able to select the secondary email address in a response - am I? It looks like it would automatically go with my primary one.
(I realise this is much easier to understand if you've got a WP8 phone)

[#7]

I've now created a separate account for my secondary email address. Problem is since this links into the same PlusNet account, when it synchronised it downloaded all the messages again - so when I linked the two accounts - primary and secondary - I ended up with a complete inbox of duplicated emails! So in theory that was a solution but in practice it's impossible having duplicated emails in my inbox and I can't tell which of the duplicates has come from which account and hence can't select which to respond to to get the right outgoing email address.
I could unlink the inboxes again - and then go into whichever I need to respond from - but as well as the inconvenience of switching between them, I'd have the phone downloading every message twice - which will eat into my monthly 3G data allowance when I'm not on wifi.

[#8]

Also discussed here I think - http://answers.microsoft.com/en-us/winphone/forum/wp7-wppeople/multiple-email-accounts-under-one-bla... - without a solution
I have been pondering whether I could set up an alternative email address (EDIT - and mailbox) at Plusnet for the secondary email address I use and divert the relevant emails into it. That would avoid duplication on my phone once the inboxes were linked. However I presumably then wouldn't see them in a single PlusNet inbox? (Which would then be a problem since I use webmail all the time from my computers;) Or would I/ could I? (I've not used any other email addresses at PlusNet apart from my original one so don't know how they're managed in webmail).

[#9]

Webmail handles each mailbox separately so for the default mailbox you login using username only. For additional mailboxes you login to each one using username+mailboxname (for password you use the one for the appropriate mailbox).
In webmail you can't get a combined view of all mailboxes.

[#10]

Sorry not to have responded. Yes, thanks - seems like I can't get a "proper" solution to the conundrum - but I'm stuck with Windows phone now having bought it.
At least following the advice earlier I've been able to get my main email address working, so it just means anything I want to reply to using an alternative email address will have to be do0ne via webmail.