It's terrific that you're switching to PD and that you work out regularly. Be sure you talk with your doctor or home training nurse about lifting weights if you will be doing CAPD and having solution in your abdomen at all times.
The Home Dialysis Central Helpful Products catalog lists one kind of PD belt:
This is only one of the types of belts. Using Google, I found others:
-- http://www.patientspride.com/ (this one is called a PD security band, but most are called PD belts)
-- http://www.worldtechnological.com/ (disposable instead of washable)
I suspect if you sew or know someone who does, it wouldn't be too difficult to make a belt. I bet most PD patients use gauze and tape to secure the PD catheter to their body.
If people have experience with any of these belts, please feel free to chime in with your evaluation of the belt(s) you've used.