Try setting his mentality to that of a 'support' striker so that he isn't isolated. Check the TT&F documents for more information on how to set a team's mentality up.
Target man isn't really needed for top flight teams, and can actually be more of a hindrance than a help if you're telling your team to try and play Villa the ball at every opportunity and he's being marked out of the game... Depends on what formation you're playing though and the style of play you're using whether it's worth having a player set to target man. Lone front men are often far too easily marked unless they are far, far better than the marking defender/s in some aspect of the game (eg much quicker, much more skillful or much better in the air).
