I just replaced all the 128 and 96 lines in the inline-uploading.php with 256 X 192 and it worked.
WP2 now rescales the thumbnail version of the image to 256 X 192.
But.. when you drag&drop or insert the thumbnail into the post its still 128 X 96.. well i can still go into the html post editor and just remove those lines, but thats just much to work..
So i did another searh for 128 and 96 and got 6 hits of .php files that includes those numbers.. i dont think i dare changing all of these, dont want to mess everyting up.