No problem digisoft, just a misunderstanding. :)

Unless you already have access to a workshop you will probably have to rig something up to grind a 45 degree angle in your supports like this guy has done:

Grinding a 45 degree angle for a linear rail with my CNC - YouTube

One problem with this approach is that you have to use v-groove bearings as wheels and the wheels will need frequent adjustment as the rail wears and your wheels become loose. The v-groove bearings are also really expensive and hard to get hold of.
It might be easier to use a piece of box section or square bar at 45 degrees as the rail like this:

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That way you can use skate bearings (just the normal wheel bearings from skateboards) which are really cheap, it wears down slower so it requires less adjustment and it means a lot less work to setup.