How about loading the original wav in some audio processing software (like Audacity for instance) and “copy-paste” the wav file parts to prepare a longer file thus making an “artificial” loop:
For example, if your wav file contains a wave W, you should create a file that will look like:
W|W|W|W|W|W|W|W|W…
Of course you will end up with a bigger wav file, but on the other hand, no need to create a package, install it, create a multipad in midi, etc.
This might serve you well if you know in advance the number of bars your loop should last for.
Of course if you make it longer than needed you should be able to stop it with the registrations.
If your WAV is a percussions/drums track, then another direction that might be interesting is creating an Audio Style out of the WAV file (again you’ll have to do it on your computer), but at least it will become an “integrated” into the style variations… I don’t have an experience with A5000 but I hope it can load audio styles.