[esp-r] Time:var graph for solar at ext face surf

[l.lars]

Hello,
I am looking for a solution to show a time-variable graph for the 
diffuse and direct radiation on an external wall.
I got a very simple model. It is just a box without any windows, with 
just an inclined roof and some shading bodies.
Is there a way to get an time-(direct solar radiation on the outside of 
the roof) graph? I just can find in the var.vsvar menu "solar at ext 
face" but nothing in the time-var menue.
At the end, this should be the import for a pv model. So I need to know 
how much radiation is available on that roof.

Thanks for your help
Lars