transitioning to new potty positions

[vireoes]

Does anyone have any tips for transitioning from holding the baby over a bowl into using a baby potty.  My DD used to potty anywhere if she needed to go and I cued her, now she really prefers being held over the bowl in our primary potty location.  We seem to manage okay out of the house.  She won't poo and will only pee about every two hours.  Eventually she will go, so now I just limit our attempts out of the house and it works fine.  In the house she likes to go more frequently ad because my wrists are hurting I would like to transition to a seated potty position.  She will sometimes pee in our the baby potty, but it is more like we are out of the house and she will hold it until she is desperate and will not poo in it at all.  She is 5 months out.  Is it a developmental thing that she is not ready to use it or does it just take a while for them to get comfortable with a new primary potty location and position?  She can sit fine on her own and will sit on the potty unsupported without any problems.    Thanks for any suggestions you have, she is getting heavy and wiggly, so I would love to move away from holding her over a bowl.

[Deepfeet]

DS is 4 1/2 months old. We were peeing in the toilet or in a bowl until a month ago when we got a potty. He didn't like it so I took out the 'bowl' part and used it like a bowl for a while, so he got used to sitting on it but with me holding him. Now he can balance on it pretty well on the floor but I haven't put it back in the 'chair' (which I should probably try doing soon. I've been waiting for him to be able to sit up on his own which he is now capable of doing...) 

Interested in the advice though...