[TYPO3-RTE] <wbr> tag not supported in RTE HTMLArea

[redacted user]

hi,

i know this is a very seldom thing, but one of my editors wanted to use 
it: the <wbr> tag. its intended to make a 'soft' break in a long word, 
but only when needed f.e. when the remaining space in a table is not 
enough. Example:

longlonglong<wbr>longword

the word will be shown like this when the space is not enough:

longlonglong
longword

otherwise it remains in one line.

i tried to allow it with RTE.default.proc.allowTags = wbr
but when saving the text it makes <wbr></wbr> out of it.

so, may be i did something wrong? Or is it not supported?
I'm using v1.3.7  HTMLArea

thank you very much!
Boris