This is a feature we have also wanted to implement, and we are still looking at how best to make this happen. We have great things planned for this app in the future and this feature will certainly be one of the new features, but please be patient as it will likely not show up in our upcoming 2.0 release.
I'd like to see that you could use different colored dices on the same throw.
Like I could have four black d6, two red d6 and one blue d6 on one throw.