Honestly I can not help you much there, I don't have a tank stick. However mame does have controls that are "default" (as you said) look into your mame folder and look for a ctrlr folder and see if you have a "xarcade.cfg" in there. If so do this:
under the
#
# CORE SEARCH PATH OPTIONS
#
look for
ctrlrpath ctrlr
make sure your path is right when pointing here!
then scroll down to...
#
# CORE INPUT OPTIONS
#
and look for
ctrlr
make it look like this:
ctrlr xarcade.cfg
it will load a pre-made setup for mame. If you want you can set it up by hand. (You'll need a keyboard until you are all set up!)
I was going buy a tankstick..but I found out that I can buy the kit and assemble it myself and save 50 bucks..yeah i'm cheap

but this way I can lay it out the way I want and use what cover I want. One day I want to build this:
http://1uparcade.rmfx.com/ and this one is cool too
http://www.beersmith.com/mame/