painting wallpaper

The foyer walls in the 1912 house we are about to buy are wallpapered over plaster. Removing the wallpaper could be a disaster (and our budget cannot handle having the have all of the walls re-plastered). Is there a good way to prep the walls to paint over the paper without removing it? I understand that an oil based primer is likely the best thing. Any suggestions?

 

one good way of seeing how suitable paper is for painting over is to spray the walls once with water using a garden spray cannister.. After about 10 mins the paper may well have lots of bubbles in it but allow to dry and they should all tighten up again...Check where the largest bubbles apeared and look to see if the paper is stuck firmly to the walls.......If it is then the same thing will happen when you paint them with a water based paint..So just go ahead and paint without priming.. If on the other hand,after soaking, the paper is loose and not stuck to the walls...Then take the advice you were given and prime the walls first only after sticking back the loose stuff with wallpaper paste.
Personally,if the water test makes the paper lift then I ALWAYS strip it and hang lining paper if the walls require it. I would urge you to do the same..There is some stuff on my site http://www.acedecor.com for stripping wallpaper and preparing walls if you need it...All the best..Toptosher!!