To provide a bit more info, there still may be a way for you to accomplish this.
You could change 190 to another extension number. (Let's use 333)
Then create an auto login calling group of 190, with overflow to voice mail and the only member would be 333.
Set the OVERFLOW NUMBER to 99 and the OVERFLOW Time to say 20 seconds (or what ever).
Make 735 the MESSAGE Receiver for group 190.
Now, after a call rings at 333, for the OVERFLOW TIME, it will go to voice mail for 190, but it will turn the light on for 735.
Not as clean as doing it with a Phantom Mailbox using R-3 Merlin Messaging, but it will work.
So