Not sure that it can be done. Both Poser 11 and Poser Pro 11 use the same program the only difference is the serial number used to activate it. I had the same issue with Poser Pro 2014 and Poser 2014GD, even putting the two programs in different locations did not allow both to be on the same computer. If you really need to you can change the serial number and activate the other version. Just make sure to deactivate the program before reactivating the other version. Your best course is to contact SmithMicro help to make sure I told will work and not use up your activations.

Poser 5, 6, 7, 8, Poser Pro 9 (2012), 10 (2014), 11, 12, 13, 14