Page layout, measurement units

[Thomas Scharkowski]

Hello all,

from the doc:

"All units dimensions are measured in staff spaces."

I noticed that I cannot change this the usual way e.g. 
"bottom-margin = 2 \cm" in the paper block.

Also from the doc:

"You can also define these values in Scheme. ...,
#(define bottom-margin (* 2 cm))"

This does also not use the cm units, but staff spaces.

"annotate-spacing = ##t" shows "20.00" and the space is the same, no 
matter if I specify nothing (spaces) or cm.

Did I overlook something?

Greetings,
Thomas

LilyPond 2.8.2, Windows XP