ADVENT on TSX-Plus system?

[Charles]

I have a PDP-11/23+ with 4 MB RAM and two RL02 drives. I can boot RT-11XM, 
then run VBGEXE and start ADVENT with no problem.

But TSX-Plus 6.50, at least the version I have, has to run over RT-11SJ, and 
VBGEXE reports "Wrong version". And ADVENT won't run by itself (without 
VBGEXE), whether SJ or XM.

So is there any way to run ADVENT while running TSX-Plus?

thanks
Charles