OpenVPN using wrong Gateway to connect?

[JeGr]

Hi,

we have a setup with a client who is using 5 Dial-In connections as WANs. So WAN, OPT1, OPT3 and OPT4 are DialUp Lines that connect via a router in front, so those networks have pfSense configured as .2 and the dialUp Router as .1 (192.168.1.1, 192.168.2.1 etc. you get the picture).
Only difference is OPT2. This one has a modem in front and is using a VDSL line via PPPoE directly and he gets a static IP on that one!
As the customer also runs a package like siproxd which relies on said static IP of OPT2, he made OPT2 the default gateway. All other WAN Links (WAN, OPT1, OPT3, OPT4) have their corresponding .1 as gateway set up correctly.
Now we configured 5 OpenVPN tunnels to a single server which is also running pfSense. All Tunnels are configured to use their specific Interface (WAN, OPT1-4) to connect to that server.

Now the strange part: I see every tunnel connecting and working BUT: WAN and OPT2 are connected via OPT2s static IP :o Somehow the OpenVPN tunnel configured on WAN isn't using its corresponding gateway but instead uses OPT2 to connect. As he uses those 5 lines to up his bandwith to said server, this is contra productive as now traffic on WANtunnel and OPT2tunnel are sharing the same interfaces (OPT2) bandwith instead of using WAN. Strange enough, all other Uplinks (OPT1,3-4) are working without hiccups and are shown with other IPs as remote IPs on the status page of the server's pfSense Dashboard.

We actually got it right about 2 times after we killed both connectivity on wan and opt2 and re-dialed PPPoE on OPT2, but after a while if you check you see WAN back with the same remote address as OPT2.

Is there anything to force OpenVPN to use a certain gateway outbound to connect? Or any clue about why only WAN is using OPT2 instead of its own gateway?

Greets
Jens