Castle Strike problem

[Lexie]

Hi,

I just downloaded the Game: Castle strike
It's the : Castle strike-immersion version.

Now I have a map, were theire are 3 sort of files:
-ims-cast(MSInfo-document)
-ims.cast.001-042
-ims-cast.sfv

Wich program do i need top open these files or to unpack??

Thank you