Photoshop :: Four-band/multispect

I work for an aerial photography/photogrammetry firm and we are looking for some solutions to working with four band images. Our plane-mounted digital mapping camera has 8 different cameras in it which fire simultaneously. Four cameras are panchromatic and are eliminated from our final image leaving us with a red, green, blue and near infrared camera. We run post processing to combine the RAW data into a 16 bit, four band tiff image.

The issue that we're facing is editing these four band images in photoshop. We use Photoshop CS, CS2 and CS3. The restrictions that were finding in editing four-band imagery are:

(a) Cannot change color, can change brightness/contrast, but not in the fourth band (alpha 1)

(b) Cannot expand the canvas to combine two adjacent images and edit without losing the alpha-1 channel (near-infrared)

(c) Cannot create layers (cannot copy/paste). This is a major problem as we often need to place a different image over a warped area of the photo and properly align it.

suggest a good workflow or available plug-ins that will enable to edit all four bands at one time?