Its nice to see that people think the same because that was actually what I did several times before posting my config. 
I tried using the eth0 local address 192.168.1.2 before or any, and switched between several combinations a few times. Didn't made any difference.
So I set it back to 'any' which then defaults in the router to the WAN IP (correctly):
$ show vpn ipsec status
IPSec Process Running PID: 1478
0 Active IPsec Tunnels
IPsec Interfaces :
eth0 (192.168.1.2/24)
About VoIP, I installed the router like 2 months ago, and the first thing I noticed is that VoIP calls broke, so I disabled the SIP ALG module and VoIP started working again. So that is the reason its disabled. My Polycom phone doesn't work otherwise.