Sorry if this has been posted before (the search function is not working on my Xoom), but when I am connected to wifi I can not send or receive MMS messages with either the stock app or Handcent. Does anyone know how to fix this?

EDIT: I was finally able to send and receive MMS messages while connected to wifi by disabling 4G/LTE. The Verizon technical support rep I talked to told me I have spotty 4G coverage at my home and I have a network extender for phone calls. I will have to manually switch networks settings until someone releases a 4G toggle widget.