iRule dependent on Link Availability

I'm currently using Link Controller to load balance ISPs. Due to the complications of IPSEC, I've had to do a config like this.

 

 

1. Pool containing IPSEC device with ip 1.1.1.1

 

2. VS created for IPSEC ports/protocols with public ip 2.2.2.2

 

3. ISP Routers are 2.2.2.1 and 3.3.3.1

 

4. SNAT pool created containing 2.2.2.2

 

5. Since IPSEC initiates some traffic, iRule created with following logic:

 

if client ip is 1.1.1.1, use snat pool 2.2.2.2 and use pool with 2.2.2.1 link

 

 

To make this redundant, I'd like to do the following.

 

 

1. Create VS for IPSEC ports/protocols with public ip 3.3.3.2

 

2. Create SNAT pool containing 3.3.3.2

 

3. Configure inbound wideIP which currently contains VS 2.2.2.2 to use 3.3.3.2 as a fallback IP.

 

4. Create an iRule that basically says, if link 2.2.2.1 is down, snat to 3.3.3.2 and use outbound link 3.3.3.1

 

 

What are my options here?