The PG-1000 transmits and receives System Exclusive (sysex) messages to/from the D-50.
As sysex can be anything the BC is not equipped to decode all synths' sysex.
But, the BC will change its parameter values if you are using CC messages.
What you need to do is put a computer in between the BC and the D-50.
Send CC out of the BC -> Computer changes it to sysex -> D-50.
For what you want to do one of the buttons on the BC can be a CC that the computer understands as 'get the current patch' and sends the sysex current patch request to the D-50.
The D-50 sends the patch data back as sysex and the Computer unpacks it and changes the values to CC messages and sends that to the BC. Now everything is in sync.
AND / OR
The computer detects a Patch Change (PC) message from the D-50 when you select a new patch and requests the newly changed patch from the D-50 and unpacks it and changes the values to CC messages and sends that to the BC.
I have done this for a couple of synths and you can have a look at the results here....
For the Korg DW6000 BCR<=>DW6k
For the Yamaha TQ5 http://www.bwalk.com.au/TQ5/TQ5.html
All the best
Royce