This tutorial originally appeared in macjams.com. Although this tutorial was adapted for GPO it may be useful for the PMI Bos290 as well. Just change the GPO references to PMI Box290 and see if it works.
I haven't tried it with PMI Bos290 but did try it with GPO with good results. If the PMI Bos290 uses an NI Player it should work.
Cool. And a very good manual you have there.
I didn't realise Garageband is 100% AU compatible. Since the PMI Bos290 Plug-In is using a NI engine it will work, now the next step is to find out how well it performs. This piano needs lots of RAM or DFD streaming, so I will check the performance soon.