Well in the short answer is NOT A FLAMING CHANCE IN HELL.

Bobasaur is right render out as .tif (alpha channel options are nice, but I cannot recall if pozer actually makes use of them), only use .bmp if you have no other option.  Go to google and search for 'open source compositing'

I would suggest Jahshaka http://www.jahshaka.org/

It's open source and it's powerful.  There is a learning curve but its's a great app.

Now the **BAD NEWS. ** Max 7, nor 8 or 9, will ever support Pozer bones riggs.  The problem is on pozer's side.  The rigg used is basackwards to the rest of the 3D universe. This is something that will NEVER be fixed.  I have it on very good authority from the Autodesk camp that they consider pozer a bug ridden pile.  And they have no intention  of ever supporting it.

The reasons, 1 a mesh out of pozer is a god awful mesh.  There is no way to fix this, aside from  remodeling the whole mesh.   Attempts have been made to write converters, but pozer provides too little information and Max requires alot more info for the mesh and bones.  As you have found some things work and others don't,  your option, live with it.  That is all you can do.

2. Pozer's texture mapping is not properly read by max.  As a max user you know how detailed and powerful the texture struture is in max, pozer is dead simple in comparision.  I have  ALWAYS had to remap a pozer dork when I bring on into Max.  Plus having to bang down the mesh to get rid of the bloody creases.
3. The pozer rigg to max - EKKK.  it's nasty.  I throw out the pozer rig and make a new one in max.  There is just no way around it.  If you think v7 is bad wait till you try it in v9.  All the improvements that were made to the max rigg structure make pozer imports alot worse.  Some people have been able to import without too much trouble, but it's a dice roll.

You asked about other software, well there really isn't any (aside from Daz).  No one wants to write software in that price range.  People are complex modeles and the rigg is also complex so unless you want to spend $$$$ you are SOL.  The only think that comes to mind is Houdini from SideFX, but it's pricey and really only imports to XSI, Maya and Max.  You option - Learn to model you own charactes in Max or buy per made & per rigged models from TurboSquid.

As for the bvh files, most of those were made from banged down mo-cap data.  Or from a pain-stakingly made animation sequence from Max, XSI, or Maya.  There are  keys in the bvh data that pozer just does not understand.  You can try and edit them by hand, since most are just text files, but that is a but tricky.  The only other option is to use Pozer Only bvh data files, those will work most of the time.

Pozer is just a low low end 3D app, it was never ment to work with powerhouse 3D packages, and most of the 3D industry does not want to deal with pozer data.  That may seem harsh, but it's reality.

I am sorry if there are no solutions for you, but it's Pozer, what do you expect.

Good Luck

Spaz