Yep, been communicating with another virtual pilot who confirms this as well. Basically, only Caucuses map works with the Harrier's AWLS. The other virtual pilot got another airfield to work with the AWLS, but he had to do some Lua Scripting. I don't doubt your statement about the Harrier being microwave based but IMHO, the manuals of the Harrier should be changed then since it's a bit confusing reading this stuff and then find out they are not working on certain maps or airfields.
I wonder what developers would say on this issue. Cheers.