No Ivan I think he cannot, I think he must elect to use his Brilliant storke at deployment time. I think it basically increases your chance of arriving, again having your cake and eating it :0)
If you play it slightly your way, maybe he should have to use his brilliant stoke before each die roll (a bit like bringing back an unreliable ally), would use up your stokes quickly.
Might be handy with El Cid in a Andalusian army.
William