Hi Nicola,
16 bit files give you an extra "safety margin" whilst you're editing them, but once you've finished editing you can save a copy as a high-quality JPEG without losing any quality.
So to answer the question, don't worry about trying to print 16 bit files (unless you do your own printing, it's a battle you won't win) ... just convert them to 8 bit JPEGs (sRGB Profile) - send them off - and enjoy
PS: Having DigitalPix's ICC profile is only of any use if you're doing soft-proofing, which - in my opinion - isn't overly useful as often printers will have significantly different gamuts to monitors, and sRGB is usually supported by both monitors and printers anyway, so usually not a lot to gain.