These are two different beasts. The miniPCI card is an internal card for which you must take the laptop apart and snap the card into a special hidden connector. The PC-Card adapter is a standard slide-in card the pops in and out of the slot on the side of the laptop.
In my experience, changing the internal miniPCI card is a crapshoot. Some laptop manufacturers have funky pin assignments or other proprietary implementations of the device, as you just discovered. Sometimes you can find one that works (or can be made to work) in your laptop, but that takes some research before you buy.
The external PC-Card adapters, though, are a different story. They work well in just about any laptop. You are well advised to check the manufacturer's support page to obtain any updates to firmware and drivers (even on brand new ones) but otherwise they generally do exactly what you expect. The only trick is to remember to turn off the original internal device - the operating system doesn't respond well to two wireless adapters trying to get its attention...