DST NAT on WAN interface from LAN network - is it possible?

Subject is probably very unclear, but let me explain.

I have following situation

Internet-----WAN(Mikrotik)LAN-----clients (laptop, server)

For example I have test page on server and I want to open it from internet (only difference is that I did not use standard HTTP port 80 on WAN interface, but port 9500).

I configured dst-nat from port 9500 to port 80 and if try to connect to it from INTERNET, for example http://www.mynetwork.com:9500, everything works fine.

But now I want to use the same bookmark from local network (http://www.mynetwork.com:9500). So packet will come from LAN interface, not from WAN interface.

The problem is that source packet (from client) has following fields set (packet sniff).

Source: Client_LAN_address Destination: WAN_address:9500

And reply packet from server has

Source: Server_LAN_address:80 Destination: Client_LAN_address

And then the client resets (RST) connection.

So as I see it, the problem is that source and reply packet go only through LAN interface and client concludes that the reply is not valid because reply port (80) and IP address is different then the port in original packet (9500) and IP address.

Does someone have any suggestion how I can solve this?

You need to set up hairpin nat
http://wiki.mikrotik.com/wiki/Hairpin_NAT