Please let me know what operating system version you have.
Also, I recommend having the latest driver install in your system, you can download the latest driver at:
its ubuntu 14.04. my understanding around whether discrete power on vs power toggle works is completely bios related and not to do with os
At this point this is not a product that we have tested with this unit so we cannot guarantee that it will work 100%.
I will recommend waiting for other users to give you some advice related with this configuration; however, I found this link that might be able to help you with this issue.