kremlinu wrote: I think it is mandatory that the paid subscription to be child of the free one.
Otherwise, the user can select only the paid plan (deselecting the free plan) and, after expiration, he will have no subscription. You must have the free plan mandatory and this is the only solution I know - making it parent. Is there another solution?

I don't have the Free plan as Parent to the Paid plan.
I have the Free plan as "Selected as default" (giving a radio button that can not be deselected)
Have a look here: www.tamiyabase.com/index.php?option=com_comprofiler&task=registers&Itemid=616

-Lars

I tested this and is working, great !
Thanks Lars