Informing server through GPRS about CSD call


Hello all,
I am wondering if it is possible to inform remote server using GPRS that CSD connection has arrived.
In my application Fastrack terminal is working as a TCP client and is constantly connected to server.
Connection is served by WipLibrary. My aplication is also waiting for incoming data calls (callSubscribe).
When connection starts even when waiting 10s before calling connectionAnswer function, GPRS connection is frozen until CSD ends.
Is it possible to send some packet to server before answering data call?
Thanks for your help.