The manual is not very clear about the ability to load ready made sample libries. However, Yamaha web site says the following:

"The end result is a Custom Voice that can be selected and played just like all the other Tyros2 Voices. For added convenience, you can auto-load an entire library of voices when you turn the keyboard on. Tyros2 ships with 4 MB of sample RAM which you can easily expand to 1 GB using standard computer RAM, giving you plenty of capacity for samples. You can even store the samples on the optional hard disk. With Voice Creator sample playback capability, you can load sample in WAV and AIFF format, offering an almost unlimited range of sounds that you can buy off the shelf."

This implies that any library in Wav or AIFF formats (with a single loop point, according to manual) may be loaded and played back. I don't know if Akai sounds are in AIFF format but there are many other sound libraries availabe in those formats. I think that someone should verify that no sample manipulation is required when loading ready made miltisample sounds into Tyros 2.