You need to play with the transfer modes. Make sure the "Modes" column is available---if it's not there right click by "Source Name" and choose modes. Darken, Multiply & Color Burn will all produce a green when those layers are combined.
"I have not failed 700 times. I have succeeded in proving that those 700 ways will not work. When I have eliminated the ways that will not work, I will find the way that will work."
---THOMAS EDISON on inventing the light bulb.