You can export texture rotations inside 3ds Max and export them into Source with Wall Worm. The steps for setting up texture rotations are identical to scrolling textures except that, instead of animating the U/V offsets, you should animate the W Angle parameter of the bitmap coordinates.

This will generate a VMT with a Proxies like this example:

"VertexLitGeneric"
{
 $basetexture "wallworm/videos/glowing_lava0"
 $bumpmap "wallworm/videos/lava_normal"

 Proxies
 {
  "LinearRamp"
  {
   "rate" "-5"
   "initialValue" "0"
   "resultVar" "$angle"
  }

  "TextureTransform"
  {
   "rotateVar" "$angle"
   "resultVar" "$basetexturetransform"
  }
 }
}

See Scrolling Textures for more info.