Normally by pressing Screen Lock + S takes screenshot in Xfire, but it's not working this time.
I tried one solution from Xfire forums, but it didn't work. http://www.xfire.com/forums/182686/topic/1446079/
As I understood correctly, I have to turn on Direct3D in ConfigEditor.exe and then open "xfire_games.ini" and replace a line "InGameRenderer=DDRAW4" under "Disciples 2 - Gallean's Return" section with:
"InGameRenderer[0]=DDRAW4
InGameRenderer[1]=D3D7"
Then save the .ini and change the renderer for Disciples 2 to "D3D7" in Xfire program.
For me this didn't work, because the renderer is grayed in Xfire.
Have anyone got this work?

There is an in-game screenshot feature, but the bad thing with this and fraps is that I can't upload these screenshots to my Xfire profile. But anyway, thanks for your help.

Just to make sure as I didn't notice this before but you put
as
InGameRenderer[0]=DDRAW4
InGameRenderer[1]=D3D7
without the quotation marks in the ini file?

sorry for late respond.
Yes, I used quotation marks, but only in this forum message. Not with the ini-file.
thanks for your respond again.

Just saw you still haven't fixed this from the commando's thread, I looked at it again and had another idea. If it works or not is a different matter. I would try changing the original InGameRenderer=DDRAW4 to InGameRenderer=D3D7. So make sure you delete those extra lines from the other solution and just have InGameRenderer=D3D7 instead.