Perhaps you should demand some of the profit from the sale of HotU.
No seriously, I suppose you should be honoured in a way, I mean a established game developer is using some parts of your module in their game. They simply thought it was good enough to use it.
And yeah, there have probably been a BioWare 'spy' playing your module at one time or another. EfU is set in the same place as HotU AFAIK, so it seem logic for them to check it out and perhaps get some good ideas.