ssh communication problem

[Petbul]

Is anybody who understand initial communication between client and server and is able to help us find the problem please ?
We have problem with Mincom MIMS (running on Tuxedo) client to server communication.
We are using TCP forwardig (SSH - Secure Shell) to get through Firewall.
We observed first TCP channel opened by MIMS client (WSL) is closed without
new TCP stream (WSH) from client to server established.
We do not know, why first TCP communication (WSL) failed.

I can send you complete dump of communication from MIMS client to ssh forwarding host, UBB config file etc...

Many thanks.
Petr
PS : Communication without ssh is OK ...