I had (and still have in proc enviroment) simillar problem in the past.
high terrain area , adverse weeather,and one runway for departing (when weather is adverse ) ,non collaborative ATC authority,and pilots that must fly at that very moment.
To avoid to lengty explanation, for us it has worked perfectly .
radar, we would like to divert due to....
aircraft, any SID deviation below MSA (we are talking about 6000 ft minimu,but in some direction fl 100 is more accurate value ) AT YOUR OWN RENSPOSIBILITY ! report completed 
If it is immediattelly after departure, than its met radar should (and do in real life ) warned him/her about CB cell in front of their nose. In that case they shouldn't depart
but they departed, and then waiting for someone else to take their part of responsibility. how yes no.
if it happens ,some time between departure and 6000, than because of high airpost elevation (close to 2000ft ) it si not big deal to reach 6000' ,and thare is no real threat,if real threat exists, than pilot either will have full ground contact (that will allow him to make his own separation )
or will climb enough fast for MSA,and than safe vectoring.
Whatever is applicable in your case,remember that nobody will bring cigarets abnd towels in jail, if you have to expalin to public prosecutor' question :
What was reason behind vectoring aircraft below MSA ???
In our legislation, only 5 years of prison.
Interesting or not,I changed airport, from rad to proc,and FL 100 minimum for all combinations.
I have had, many of such cases( our summers are excellent,Cbs appear only in the afternoon
) and
below FL 100 at your own rensposibility
works even better,once they learned that rules are rules.
so keep it to doc 4444,if it is ok for local authorities than it is even more ok for us.
