Do you soft proof using ImagePrint profiles in Lightroom? I don't know if that is even possible, but it is in Photoshop. If not, do the soft proofing inside IP. Try lifting deep shadows, as a starter. You might also try printing directly from LR, using the Canson profile, just to see if there is a difference. Finally, if all else fails, call ImagePrint support and discuss the situation with one of their tech people. Telephone support is one of the perks that you paid for.
Rob