Horse won't let me put cream on leg?

Today my horse was prescribed some dermisol cream from the vet, to go on a lesion thing on the back of his knee (basically its mud fever which didn't heal properly). He won't let me put the cream on, every time I try he constantly moves, jumps, kicks out, and squashes me against the wall (not fun when he is a very heavy 15hh shirexcob). So far I have tried to have someone else hold him, give him his feed, give him his lick, let him eat grass, have someone else hold up another leg so he (hopefully) can't move around so much - whilst I try and put the cream on, none of these have worked, So any ideas how to get the cream on him?