it's very difficult to add characters outside plane 0 (the BMP)

I'm trying to add characters from the Akkado-Sumerian Cuneiform block, which begins at U+12000.

Pasting the characters into the editor doesn't seem to work. (I have no idea why, but personally I'd rather write my .flash files manually anyway.)

When editing .flash files manually, no reasonable encoding works (that I have found). UTF-16 (LE & BE) and UTF-8, with and without the BOM, don't work. Addition of one of these would be really nice.

Using \uXXXX-style notation doesn't work with the actual codepoint. \u12000 is interpreted as \u1200 followed by the digit 0.

The only working input method I have found involves converting a plane 1+ codepoint to its surrogate pair equivalent--equivalent to converting the codepoint to UTF-16, then hexidecimal \uXXXX notation. It works, but it's horribly tedious.