AKAI LPD8 Garageband and Introduction

Hey guys, I'm Dave. I've been browsing around here for awhile and everyone seems very knowledgeable and nice. I just bought an Akai LPD8 and I also have the LPK25, my main attraction to the LPD8 was the knobs as I had never used anything like it before. Although when I plugged it in the only knobs that worked really was the K1 and the K7, for modulation change and volume control. Now the box said that the knobs could change virtually any parameters. I'm not sure whether my inexperience with these types of products is the problem or if Garageband just isn't up to par. I am looking to upgrade to Logic 9 in the near future, but for now I am happy with Garageband. Is there any way to easily map different controls onto the LPD8 or am I stuck with the two functional knobs that really do not help me. Thank you very much for your time, I thought this was the right place to post this as I want to "map" different effects onto the knobs.
- Dave