You are in the dark, I've had similar problems with the 5528/4428 the documents are not always matching the real world. sometimes you will find two or three versions for the same card, while each suggesting different APDU sets and each will be correct or wrong in several of them. it's not going to be a fun entry into this domain. other times the documents won't reveal to you some missing detail from the connection procedure. which means that you probably won't be able to establish connection half of the time. but then if you look at the code samples in the SDK you suddenly see what you acutely have to do...
As for the SDK... you can buy SDK for the ACS reader/Card you are planning to learn. don't get me wrong, it's not that the SDK is written very well either. in fact, often you won't even be able to compile some of the code samples unless you fix some syntax errors. and even after you got trough that, sometimes there are bugs in the code samples.
One more thing, I wouldn't bet on their tech support, you'll get almost automated response which usually makes no sense at all. although they've changed the contact person now, perhaps you will have more luck then I had.
The good news are that once you got it working, it will likely do good in production.