KH pictures

I was just looking through the cool link KHR sent up with all the pix 
of various forces involved in Afghanistan etc. 

Questions:
USAF STS - who are they and what do they do? Never heard of them 
before.
SEAL DPVs - SEALs with desert patrol vehicles.... that's like alpine 
troops with fruity drinks with umbrellas in them....??
VBSS Missions - ??? What's this in real human language?
KSK equipment - Is one of the top pix of a guy on a vehicle with an 
HK-36 with a drum mag?
Royal Marine Commando Picture #24 - What's the weapon? A cutdown 
M249/minimi?
Swedish SSG - Special forces? 

http://www.cellnine.com/pender/web/oef/oef.html for reference. If you 
didn't visit, you should. Very cool. Just wish they hadn't blocked 
out all the faces (I understand why they did, it just kinda spoils 
the image).