Please help with dst-nat!

I have private Ip’s to my users. I use masquarade. I need to redirect all Http traffic to webserver on second interface (Not WAN) with Public IP. If I use Public Ip’s for users instead of Private all is OK.

‘ip firewall nat add action=dst-nat chain=dstnat dst-address=public_IP protocol=tcp dst-port=80 to-address=local_IP to-ports=80’.