stooo,
Can you post your PIX model, IOS version and VPN Client version.
From what I know, pre IOS v6.3(2), you cannot provide internet access to a VPN Client unless you use a PROXY within the network the VPN Client comes into. The PROXY will "request" the webpage and "foward" it to the VPN Client. In this manner the VPN Client never uses it's own connection to access the internet.
Is this available in later, post IOS v6.3(2), I'm not sure, maybe someone can shed some light on this.