I'm having the same issue, but it appears that any field I create doesn't show up (even when I was creating the custom form type for the first time). Does anyone know a way to get your own fields to show up in the custom registration form type fields?

It would be helpful, I'd rather not have to create my own custom registration module... I've done that in the past and it makes every major upgrade a pain.

 

Update:  I added another field and this one was just plain old text.  That one showed up when adding to the custom fields... my other two fields I can't get to show up are a checkbox and a list.  So, maybe this is related to the property type.  What type is the property you can't get to list in the custom fields? 

Yes, the Custom Property in question was set to visible.

After playing with the Custom Properties and the Registration Fields for awhile, I found out it only works if the custom property is of type Text.
No other Data Type will work, not even Multi-Line Text or List.

Not sure if this is a bug or a feature....