PCC with incoming VPN from intrenet

I have following scenario.

Internet >> >> Mikrotik VPN SERVER with PCC (2 WANs) << >> Office Network

I want to connect to my network from home using VPN. but it does not work. If I disable PCC , the vpn connect fine from my home pc.

What need to be done? Can any one please guide or post some examples ?

http://forum.mikrotik.com/t/pptp-vpn-bridge-and-pcc/39523/1