Well Nexon hid their process from anything and everything so.... I'll leave this here to toy with and if you manage to monitor engine's winsock lemme know =p
Credits: Suprathief for the guide.
1. Download Wpe then open it up.
Link to WPE from WPE site. IT will say it has a virus -_- WPE PRO
2. run hackershield bypass and open up combat arms.
3. Now alt+tab out and select Engine.exe as your target which is combat arms.
4. Log in game and create a room.
5. Press this button that looks like this |> like the play sign.
6. You are now recording packets. Go in game and change the map.
7. Alt+tab back out and press the red square.
8. Now your packets should appear. Look for the send one. Or the packet with the label send on it.
9. You right click that packet and click add packet. Also right click it again and select use as socket.
10. Double click the packet that you just added it should be labeled. New Send.
11. It should look roughly like this.
4C 03 00 00 0E 00 00 00 4C 03 0E 00 00 00 02 00 00 00 XX 00 00 00
with out the XX though.
12. Now you see where the XX are. At the 19th byte you change it to map you wish.
13. I'll provide you with numbers
03= Two Towers
07= Sand Hog