I just want to say, that my mesh network is up! Thank you for answering my questions. 
I configured my ZNet 2.5 development kit with the ZB firmware (one XBee module is a ZB coordinator, one is a ZB router, another XBee module is a ZB end device), and the the stack profile is set to 1 (ZigBee 2006).
I also configured my ConnectPort X2 with ZB router firmware.
I got some Texas Instruments boards with the CC2430 chip.
They are all together in one mesh network and communicating.
So far everything is working for me! 
Regards
Simon