you would do it like this, type these into the init box
scudname Action ["SCUD LAUNCH"]
that makes the scud point skywards (if you just want it raised and not fired) and
scudname Action ["SCUD START"]
makes the scud launcher point the scud skywards and then fire it soon after.
NOTE: replace scudname with whatever you named the scud. so if i named the scud BigRocket then i would type in the init box
BigRocket Action ["SCUD START"]