To get an external waypoints to appear on the NavNet VX2, the "talker" needs to output the RMB sentence. There is also a menu setting in the NavNet VX2 that must be changed so that it will read the incoming RMB sentence. Since you state that the NavNet VX2 is seeing the waypoints from the GP33, that menu selection is set correctly.
The GP33 does output the RMB sentence, but the RD33 does not, at this time. I spoke with our Product Engineer and he confirmed that this is on the list to be added to the RD33, but there is no time frame for when this change will be made.
If this is the only thing that is not working, then there is nothing wrong with your system. However, if there are other functions that are not working as you think they should be, then as Johnny Electron requested, please provide more information about how all the components are connected as well as more specifics about the issues.