Most wheat extract is around 60% pale and 40% wheat so that alone would be close.
You could mash the Malted wheat with the unmalted wheat. American Malted wheat has very high diastatic power. Flaked wheat will work best for the unmalted protion. I would mash it in a bag so you don't have to worry about a stuck mash, almost like steeping grain.
Everything is better with a beer.