vbcode: /me substitution

I'd like to have a equivalent to IRC's /me function, and allready tried several options in vbcode, but can't get it to work.

vbcode:
<font color="red">~ $bbuserinfo[username] {param}</font>

user input:
[me]is very tired[/me]

output:
~ djr is very tired

However, I can't get the username to display. Is this possible at all in vbCode? How can I get the username parsed? I tried with $post[username] and several other options, but it just displays:

~ $bbuserinfo[username] is very tired

grrr... any help?

- djr

[djr]

anyone?