Enable exec() for one domain

Hello all,
Is there a way to enable exec() for one virtual host on a server? Safe_mode is on globally and exec() (and other fns) are disabled globally. The PHP docs are a little hazy, so I thought I'd ask real people.

Also, safe_mode is supposedly disabled for my virtual host, but it seems exec() and company are still disabled for me.

Any help is greatly appreciated.

Clint