Checkout my Worldmachine Preset and my Material. I'm rendering out the Masks for the detail layers with Worldmachine and the Coastal Overlay Plugin, which i modified slightly. So with my Setup you dont need to paint any detail textures per hand at all. But you could still edit the Masks in Photoshop or something similiar.…
just use a LinearInterpolate node in your material. read the UDN materials compendium page to find out more about it that method cannot be used to apply vegetation though, but neither can the "painted layers" method. to apply vegetation it must be placed using the Foliage tool, and all relation there is to the landscape…
As it is a mesh then you wont be able to edit it with the landscape tool, but if you finished all youre editing in landscape mode before, that won't be necessary. The only thing you could do is edit the mesh in 3dsmax(or similiar apllication), or maybe export from udk as heightmap(not 100% sure thats possible) to a…