Problem with Trust Relation Ship in Server 2003

Hi to All,

My question is regardinig with TRUST RELATION SHIP between different Domains

I am Working as a system administrator in a gaming company....

We have one server with the name of "Test.com"...around 90 systems have there clients...I install windows server 2003 in one of the client system with the name of testing.ch..

So, that client has two operating systems one is Xp another one is server2003..

I create one user in server 2003 with the name of "testinguser".he is working fine in that server...he is also member in test.com...

when he login in test.com server,he have to access Internet,share server and he have to receive policy that i apply through GPO...

when he login in Testing.ch with "testinguser" he cannot able to access internet, share server access like any service which he have the access from test.com....

I think it is possible with "TRUST RELATION SHIP"...

For that i Configure Two way trust relation ship in Testing.ch server...is it nessery to configure trust relation ship in Test.com?

After complition of configure in trust relation ship user have two options in Login screen...

I entered USERNAME:Testinguser
PASSWORD:**********
DOMAIN :Test

When click on OK it shows Bad user name and password

I configure Trust relation Ship in only TESTING.Ch not in TEST.COM....is this problem...

So,my requriment is only one user like "universaluser".

He have to login in TESTING.CH as well as TEST.COM with same credentials and another thing is,

He should have access all resorces from Test.com when he login in TESTINIG.CH as well as he should have access all resources from TESTING.COM when he login in TEST.Com

How to resolve this problem..

Please help me...

Thanks in advance....