Bracketing part of a BassFigure

[Daniel Rosen]

\version "2.17.27"
\figures { <6+> <[6+]> }

The above produces "#6 [#6]". Is there a way for me to have JUST the sharp 
symbol in brackets, "[#]6"?

(This exact question was asked on the list a while ago 
(http://thread.gmane.org/gmane.comp.gnu.lilypond.general/64125/focus=64139), 
and the person who asked it was essentially told "no." However, only one person 
responded, and so I thought I'd ask again to see if anyone else has any input.)

DR