Ok, I have made an alphaed tif file. What I want to know is how to set it up properly ingame. (conserning the .bitmap tag and the shader tag. I don't know which shader to use)
Help would be apriciated.
-Thanks

It is a tiff with an alpha channel?
Depends what you want to control with the alpha, transparency or detail map control?
Open the .bitmap in guerilla and change to explicit alpha then run through tool again.

Ok, I have already done this, but what do I do with the shader. What type of shader do I use.

By the way, this is just a completely transparent alphaed texture that is for an invisible ladder. Well there is a ladder, but it is actually modeled in and has no collision.

Soooo....you want the entire shader to be transparent? Look at any of the shaders for the original campaign with "invis" in the name and use their bitmaps in the way they use them.