Comprehension question concerning redundant vpn tunnels

Hi,

I've a question concerning redundant IPSec tunnels because of my experiences with Bintec routers.

-Site A with two independent ISP (ISP_Aa and ISP_Ab) connections
-Site B with just one ISP (ISP_B) connections
-Both sites have Bintec routers.

There are two IPSec tunnels, one from ISP_Aa to ISP_B and one from ISP_Ab to ISP_B. Both tunnels are up concurrently! At each site there is a load balancing between the two tunnels.

At site A I'd like to switch to an UTM9.
When I read here about load balancing / multipath rules I get the impression that UTM9 is not able to establish two tunnels in parallel and to balance traffic between them. There's just the possibility to automatically swith site's A tunnel endpoint from ISP_Aa to ISP_Ab and vice versa.
UTM can only do load balancing / multipath rules on the ISP interfaces only, not on the two tunnels?

Am I right?

Thanks
Xavier