Hi,
I'm sorry to break your fun, but this was already discovered a long time ago. Basically, missions that don't have the extra new WWP triggers, can also be played in WA: these are at least
2,
36,
39,
40,
41,
42,
43,
44 (Youtube links). As you see, these were played in W:A.
The rest are either partially or fully incompatible with WA, because WA doesn't have the new triggers and effects from WWP (such as the famous mine cannon), therefore you lose mission content.
Also you didn't mention the need of using the
wkFileOverride.dll module (it's required to redirect WA into loading the local DATA files instead of CD:\DATA files), which means that you're either a Steam user or modify your disk image,
or a pirate.
Also you can use any PNG file as an IMG for your mission. Just load it in the map editor and then grab the
uncompressed custom.img file from the W:A root. The compression, if required, can be performed via external tools, the algorythm is described on the WKB.