After spending quite some times trying to integrate F5 BIG-IP VE into VIRL without any success..., I did manage to deploy another SLB virtual appliance into VIRL, the A10 vthunder KVM edition, which is working just fine !!
You just need to deploy the iso image into your KVM hypervisor first, and then run the install script. Once finished, compress the vthunder.img (from /var/lib/libvrt/images) and upload it into VIRL, using this specific subtype :
So far, I tested it using a very simple topology : 2 web servers (based on a custom servers image), vthunder deployed in routed mode between my client and the servers, VIP service using round-robin SLB algorithm towards my 2 web servers :
I'll now test some advanced features as well as one-arm / transparent deployments in the coming days...