You can do it all right in Poser.

Off the top of my head.

Load the character that you want to convert them to. Turn off ik, select the body, open the joint editor and zero the skeleton. Close joint editor.

Load the boots, do not conform them.

Pose, scale the boots so they are in the right spot and fit the character. Don't worry about poke thru yet, just the general fitting of the foot and shin..

Go to the fitting room

Start a new fitting session

Select the boots as what you want to fit, uncheck zero.

Select the target as the character you want to fit them to. Check zero

Click create character. (don't run any fitting)

Select hip to feet bones, toes are optional

Turn of transfer morphs, turn on autogroup and zero

After Poser finishes fitting them go back to the pose room

Open the hierarchy editor.

Drag the bottom of the skates and then the pom pom from the Roxie boots to the new boots foot on both feet.

Delete the character and the Roxie boots (Not the new ones)

Save the new boots.

reload the character you are fitting them to.

Conform the skates to the character and create any morphs that might be needed.

Resave the boots under a new name and recheck them.

Your done!

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