Well, from memory here as I am not behind Poser right now.

Rex and Roxie use bulge maps in their collar-shoulders and in the hip-thigh area.

Transfer the weightmap using the setup/fitting room, and transfer the bulge maps using the "Copy Joints from" function. You need both for close fitting clothing to behave.

Only start "painting" after you are sure that you have transferred both maps.
Normally, no painting is required for close fitting clothes after you transferred both maps.
But you never know.

Deformers = the magnets. (Not the weight or bulge maps.)

If you are using your own "donor" pants, => => => Be sure that they have IT all => The weight maps, the bulge maps, and the magnets, before using them as a "donor".

Poser 1, 2, 3, 4, 5, 7, P8 and PPro2010, P9 and PP2012, P10 and PP2014 Game Dev
"Do not drive faster then your angel can fly"!