I haven't looked at the particulars, but since RtCW and MOHAA are both quake based, you may be able to use with MOHAA already. From the description, it sounds like WAB takes your file locations in a config file, so it shouldn't matter to it whether it's feeding rcon commands to a MOHAA server or an RtCW server. Just get a freeware copy of perl for Windows (the author of WAB lists where you can get them in his zip file).
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"If your philosophy does not produce corn, I don't want to hear about it." - Red Bear