Reg:Third party application redirecting to portal desktop

Hi ALL,

We had a  third party application( IPHeaderLoginModule ) in which we have USER NAME and password fields.

After entering those details and if i click on submit button it should redirect to portal desktop after validating this user with the j2ee engine .

But its redirecting to login page  and again where it asking for loginId and password once again .

And where we need to maintain proxy settings for redirecting .

Can any one help out on this .

we are using portal 7.4 v

Thanks & Regards

Deepika