You don't have to save your model as a preset to export it, just hit the 'E'dit function and when the window pops up that allows you to smooth or unsmooth the model, hit Ctrl+D and the save-as window will open, select the file format you want to save as and it will save the model.
But like I said, for the .x format any texture info is disgarded and I have yet to manage to load a .x file exported this way into se5 or starfury. so It just doesn't work.
I mention saving objects built within bryce as presets so that you can then just select then from the presets to include in new scenes.
Cheers!
