Trackpad/Touchpad Attachment?

I am in the final stage of planning for a mod on my Latitude E6400 trackpad to convert it from an Alps to a Synaptics. I was wondering one thing about the structure of trackpads, and can't seem to figure it out.

Do the parts of the trackpad physically include just the small board directly under the pad, or does it also have the actual tracking surface as part of the assembly?

In other words, what exactly constitutes a trackpad? If I want to remove the part that would actually change how it registers to touches, etc, would I have to remove just the board or the board AND the physical surface on which fingers are moved?

My reasoning is that many modern laptops have the touch surface built right into the palmrest/casing, indicated by a little indent or something. There's no physical surface to remove in this case, because I'd have to cut the case. So, I was thinking that possibly there are just sensors on the bottom of the plastic that register pressure...

Any advice is appreciated...

 

Hmm, I dunno about newer machines, but on the Latitude D600 and D610, the touchpad was a separate piece attached to the palmrest. You had the touchpad module, a small daughter board for the buttons, and then a cable connecting both of those pieces to the motherboard. You couldn't break up the system into more pieces without physically breaking something.

Dunno if that answers your question, but yeah...

 

Ok. So on the older models, you're saying that the touchpad surface was directly attached/soldiered to the touchpad board.
Any idea about how that entire board+touch surface assembly is attached to the palmrest? Glued?

 

Nope, just screws. I can take some pictures this weekend if you want.

 

That would be great, thanks! I'll dissect my old Inspiron 5150 meanwhile and try to see if I can find some type of consistency.
Meanwhile, I'll order that Vostro 1500 palmrest I've been looking at...