Thompson Gateway TG585 V7 Port forwarding Problems

[#1]

Hi guys just had plus net send me a new router namely the Thompson Gateway TG 585 V7.
Internet connection is great speed is improving as on the ADSL2+ Trial but still connection stable.
I can connect to Xbox live fine and download demos and such, however  my NAT type is STRICT and this limits the games i can join and prevents people joining my games.
Ive followed the closest guide on port forward.com to forward ports 88 and 3074 but for some reason the NAT reains STRICT and thus far all PN support cld do was give me the number for XBOX customer support not really going to help.
Does anyone here have any experience with this particular router im pulling my hair out trying to get some games online.
Thanks for your time.

[#2]

It is possible on that router. This link indicates what to do...
http://www.fightclub360.co.uk/showthread.php?t=9072&page=3
Basically, as it says there, don't use the port forwarding. It will only work with upnp and you must not set a static ip in the xbox360. Once the xbox360 has connected to the router, in the router web interface you need to set the xbox360 to always get the same ip address from dhcp.
Cheers.

[#3]

Thanks for the added info Tomm tried the setup you mentioned and still no joy  it seems this is doomed im starting to think the router is faulty as my friend has the identical set up to me and on plus net and his router was just plugged in, set up and ran.
Anyone else got ideas on this perhaps some Plus net steff out there seeing as you guys supply the router someone must have a way around this one.
Thanks for your time

[#4]

You could try the suggestion here. If that doesn't work then drop me a PM and I'll see if I can get hold of a copy of the version 8 beta firmware for you to try.