Ok, no-one else seemed to be able to help so I'll give it a try.
I've no direct experience with the Samsung but O2 have a guide for setup here
http://mobilereviews.o2.co.uk/devices/device.jsp?deviceId=604&tab=8&step=2&settingId=2830 and a guide for non-o2 ISP's here
http://www.o2.co.uk/ISPsettings ( just use the pull down menu to select PlusNet ).
Now they refer to using 'screen name' in the account username field. My best guess is that it would be your username and password for your PlusNet email account as you would use to login to webmail i.e 'account+user' .
Hope that helps
Superusers are not staff, but they do have a direct line of communication into the business in order to raise issues, concerns and feedback from the community.
