In Photoshop open both, the normal and the mask together with your image from Mojoworld. Select one of you renders and Ctrl. + A to select all then copy to clipboard memory then select and paste into your Mojoworld image. It will come in as another layer. Now do the same with the other image. Now in the layer that contains the mask you can do one of several things; using the wand tool, pixels set at 32, click in the black then invert selection to select only the white and save that in the channels palette as a selection for future use. Or you can make white your foreground color and in the select menu use the color range tool to isolate the whites, click OK now save this as before in the channels palette as a selection. If you have Photoshop 7 you can use the extract filter to extract the tree but this tends to be a bit more time consuming as is using the pen tool to first create a path then a selection. Now that you have your selection saved in the channel palette, you can highlight the tree render layer in the layers palette and Ctrl. + click in the saved selection layer in the channel palette to select the tree object. Once your tree rendition is selected you can now copy to clipboard memory and paste right into a new layer the tree all by itself. You may have to fiddle a little with the selection in the layers menu to defringe or remove white matte. Also, remember to clear your selections often otherwise you may have some strange things happening.