i suggest:
0. create a snapshot of vm (just in case...)
1. install Netapp-Host-Utilities (if not already)
2. enable MPIO within Windows Features
3. enable MPIO support for ISCSI-devices
4. install Netapp-DSM (the MPIO stuff if you want to use it from netapp)
5. reboot system
6. add second NIC to VM and configure it
7. configure ISCSI within VM to use also the 2nd NIC
that's it.. good luck!
-AJ