Sorry my brain 's left me again

How can I use an entity skill as a string??
I'd need somethin like:
Code:
string terrain_shadowmap[30];
str_cpy(terrain_shadowmap,"terr_");
str_cat(terrain_shadowmap,my.skill10);
str_cat(terrain_shadowmap,"_shadowmap");
str_cat(terrain_shadowmap,".tga");
But of course that "my.skill10" there won't work

Any suggestion appreciated...