Try this out- 7-1-1_Trading_Networks_Administrators_Guide
Retrieving the Partner’s User Name and Password
The following is the procedure you need to perform to retrieve the partner’s user account
information (user name and password) from your Trading Networks system.
1 Select your partner’s profile. If you need procedures for this step, see “Finding and
Viewing Profiles” on page 582.
2 Select Trading Partners > Show Password.
3 Trading Networks displays the user name and password for this partner profile.
Record the user name and password.
If no joy we can do this
Attach the binary encoded password of a particular Partner and lets see whether we can try to de-crypt using java services. 
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