LDAP E-Directory and WS-Security

I am working on a program that has to communicate with other program's.

For starters:
You log on to a portal and E-Directory checks your credentials, if alright myapp starts. Myapp has connections/interfaces with other programs. To send a message from app a to app b, E-directory/LDAP interferes with the proces.
How can I send an impersonated message to another application with the use of E-Direcory/LDAP. And can I receive answers from the oherapp to myapp ?

Has anyone got a briljant idea or a good example for me ?

Thanx
Herman