Route ISA -> Mikrotik

Hi All,

I need help to set routing between Mikrotik and ISA in internal network to route to VPN network…
I have VPN network, LAN2 have Mikrotik and ISA connected directly to internal network. And ISA connected with Mikrotik directly. If computers in network have static route to LAN1 - all ok… but when static route doesn’t exist, traffic go to ISA and ISA route traffic through Mikrotik. Now i have trouble with response traffic… his going directly to computer, whos send connection through ISA server, but ISA deny packets with SYN attacking…

I want to route traffic from Mikrotik to LAN2 to initiated connection computer… if traffic go through ISA - return his to ISA