Specularmask for Blendtexture with $blendmodulatetexture ?

I’m currently working on a snow-rock-blendtexture using a $blendmodulatetexture:

http://cloud-2.steampowered.com/ugc/595877960899865589/F3AB9FC244D3411E36F6C857451D9C573A0E1768/1024x576.resizedimage

In order for the snow to look good it needs to have a specularmap (see image below),
but since $blendmodulatetexture is incompatible with $normalmapalphaenvmapmask and the alternative $envmapmask can’t be used with a $bumpmap,
the only option that remains is $basealphaenvmapmask which can’t seem to work either.
Does someone have any idea how to get all 3 textures (Diff-, normal- and specmap) to work with the $blendmodulatetexture?

http://cloud-2.steampowered.com/ugc/596998708816645317/AFDC39121CB43EE76BCC95B0687DE7F258793F07/1024x576.resizedimage

Thanks in advance!

I remember a friend of mine having this problem a few months ago. Not sure how he got around it, but you can ask him yourself if you want.