Need to find Session code

Hello all.
I am in session tdpur4100m00 and I copy an order using tdpur4201s000.
I am writing an extension and I need to have the session code of tdpur4201s000.
I am using

string sessname(15)
import("prog.name$", sessname)

but this is giving me the parent session tdpur4100m00 although I am doing a copy order using session tdpur4201s000.

Please help me.
Maria