If you don't want an exact copy and only want the plasterhand for modelling, you can wrap up the hair with plastic wrap.
Do you mean clingfilm? (for wrapping foods) I tried it on the skin some time ago when painting latex onto my arm and it didn't go well! 
But OK with plaster it might work!
But OK with plaster it might work!
Eyupp, that's the one. I guess latex is too thin and runns off?
I was using 'cream' latex , and it did seem to stick ok to the clingfilm.
The cling film started wrinkling up and making a right mess.... I had put vaseline beneath the clingfilm (on my skin) as I though it might help the clingfilm stick....(probably a mistake)