internet connection sharing

I am working on the windows xpe image and i need to check the check box for "allow other network users to connect through this computers internet connection" found in the Advanced settings under the Internet Connection Sharing.
It works fine when i run the image on the single wireless card but as soona s i change my wireless card that particular check box is again unchecked.I need to know from where exactly its is displaying eth value of ethat checkbox and why it is being unchecked.If i gain check it it pops up teh message that internet connection sharing has been enabled for wireless network connection .Do you want to eanable for wireless network connection2.

I digged it into the regisrty and found that taht are two enteries for both the drivers and i dint find any reason why it should be unchecked.

Can somebody tell me how all this internally works.is tehre any registry key,some tool,some utility ,some command or soem Apis by which i can set thsi property automatically or it should not reset when i change the wireless card.

Thanks in adavnce for your help
Devika