Ftp problem, cannot connect to lan server via wan ip

[ders]

Hello community,

sorry for this weird subject, but unfortunately I was not able to find a solution for my problem until now.
I am running PFSense 1.2.3.with one LAN and a WAN connection. A No-ip task is running on the WAN side to give the opportunity to connect to my ftp server.
I configured WAN and LAN rules so I am able to connect to this FTP server from the WAN via passive mode. VSFTP is running on this server, but I am not able to connect to this Server from my LAN with a lot of FTP-Clients. The server is located in the same LAN like all other clients. 10.10.12.0/26.
I think the problem is, that the passv_address is the wan address and not the expected LAN address, but I can not change this, otherwise no one from the WAN will be able to use this FTP service.
So now my question, is there a chance to setup my PFSense for using the FTP service out of the LAN?
Hope someone can give me a hint.

Thanks