Have a look at the next version (9.3) of Awave Studio. It can read out AKAI, Roland or Kurzweil. CDs are shown like in explorer, layers as subdirectories. Converts directly into sts Format.
The CDXtract I've got (v.4.2.1) converts to STS using .s (samples) and .p (programs). This is the old akai style format previously used by CW samplers. I've been after CDXtract for years to update to the current STS format (.wav & .sts).
Welcome H-Rave. You're right, SFP can convert AKAI to STS, but only up to AKAI 3000 format. Maybe the AKAI 5k or higher samples are not convertible or readable in SFP, but I never tried that.