guitar guide-mark

[Peter Buhr]

When writing the fingering for guitar, there is a notation used to indicate a
guide finger in left-hand shifting. The fingering mark looks like "-3", but the
"-" is rotated up about 30 degrees, which means to silently slide the 3rd
finger from its previous position to this marked note on the same string. (Just
in case someone doesn't know. ;-) So I want to write something like:

   c-{-3} or c-"-3"

The first doesn't work and the latter puts the "-3" below the note. Is there a
mechanism to accomplish this? Again, I have scanned all the documentation and
not found an example, but I could have missed it.

Cheers