Unfortunately, I am fairly certain that E-Junkie can not handle variants for digital products. At least it couldn't several months ago when I was developing a website that could have really used this feature.
You can see an example of this integration by visiting one of the pages that uses it:
If you would like help setting this style of integration up on your own site, please just drop me an email or give me a call using the contact information on my website. It would be very easy to modify the code so that it would give your customers a choice between two versions of your downloads.
I hope this helps.