Vertical alignment of Incipits no longer working

[Reinhold Kainhofer]

In the LSR there are two examples for incipits:
http://lsr.dsi.unimi.it/LSR/Item?id=582
http://lsr.dsi.unimi.it/LSR/Item?id=348

The first one was written by Nicolas Sceaux, who generalized it to his clef-
keys.ily package to produce critical editions showing only the original 
clef/key for a voice. 
Unfortunately, the vertical alignment of the scores inside the instrumentName 
property no longer works in Lilypond 2.13.x: The staff lines of the incipit are 
no longer aligned with the staff lines of the normal score. Instead, the whole 
incipit is vertically centered at the middle staff line of the score. This 
works if the clef does not extend beyond the staff lines, but for e.g. a treble 
clef or a soprano clef, the incipit will be off (since the vertical center of 
the incipit is no longer the middle staff line.

It seems that the middle staff-line of the incipit is no longer set as the 
reference anchor point for the vertical alignment, making it impossible to 
vertically align the two staves...

Any idea how to solve that issue?

Cheers,
Reinhold
-- 
------------------------------------------------------------------
Reinhold Kainhofer, address@hidden, http://reinhold.kainhofer.com/
 * Financial & Actuarial Math., Vienna Univ. of Technology, Austria
 * http://www.fam.tuwien.ac.at/, DVR: 0005886
 * LilyPond, Music typesetting, http://www.lilypond.org