Installing Pro license on a virtual machine

Hi,

I'm trying to set up an autobuild for our Unity projects, which I'm going to run on a virtual machine. I've got it all working nicely, but in order to get it to generate android builds, I need to transfer a pro license onto that machine.

My question is, given that the licensing is done by Unity when it starts up, and I can't start it up without it complaining about not having access to a graphics device, how do I install the license? It kills itself after complaining about no DX device, and if I specify -nographics and -batchmode (which it needs specified together) there is no UI at all, and it never prompts for activation.

Is there a way of doing this that I'm missing?

Cheers,

Graeme