Zentyal keeps changing my default gateway, how can I prevent it?

[creatron]

I have three external Wans with failover enabled.  If the one wans (RF) sometimes goes offline, the internet stop, because "somebody" has change the default to the RF wan.  I want the primary WAN wan to be the default as the RF just a backup., but I need to reset the
default gateway almost daily.

I use Zentyal 2.2.3.

What I cannot understand is the system is suppose te recover and use the "other" networks as well.  The cellc is a 3G USB stick that is expensive and only inserted if both "other" WANS is offline. I only have two wans available normally.

Gateways List
-----------------------------------
Enabled  Name         IP address       I   nterface  Weight Default Action
             neotel          192.168.0.1              eth2        1       no
             celc             192.168.123.1           eth1        1      no
             ppp-gw-eth3  ppp0/41.208.205.53  eth3        1       yes
------------------------------------
Balance traffic is DISABLED
    as this enable a huge can of worms (https ?)
----------------------------------
Global options
Time between checks:  60 seconds

You can define different rules to test if a gateway is working properly.
If one of the test fails the gateway will be disabled. It will be enabled again when all tests
are passed.

Enabled Gateway      Test type        Host               Number of probes Required success ratio    Action
        ppp-gw-eth3    DNS resolve   creatron.dyndns.org     6                   20 %
        neotel            DNS resolve   creatron.dyndns.org      6                   20 %
        celc               DNS resolve   creatron.dyndns.org      6                   20 %

Events is enabled and I can see the system change from one to another if I unplug the wans. However, if the network goes offoline, the default setting has changed, if I reset the default the system is online again.

Thanks
Gerrie

Thanks
Gerrie