Edvard,
Assign values to the Radio options:
All = 1
This month = 2
From today and rest of your life = 3
Then in the embed point Generate Form - Start put something like this.
if p_web.gsv('l:StatusC') = 0 ! If you do not want to overwrite the status if it is already set
p_web.ssv('l:StatusC',2)
.
You probably don't have to assign values then p_web.ssv('l:StatusC',2) becomes p_web.ssv('l:StatusC','This month').
Cheers
Charl