Increase vertical spacing between systems

[Hartmut Leister]

Hello Lilypond users,

I'm having a vertical spacing problem.
For a simple score (see [1]) I want to increase the vertical space
between stanza 2 and the next system (I've marked an occurence) just a
little bit.

I've looked into the documentation [2], but it doesn't seem to work.
What I don't want is to stretch the systems, like with
> \paper{
>   ragged-last-bottom=##f
> }

Thanks in advance.

Hartmut

[1] https://www.dropbox.com/sh/f2rw614acsglg7i/AABvKYjtNB-1DbZo2LPA2l_Ta
[2]
http://lilypond.org/doc/v2.12/Documentation/user/lilypond/Vertical-spacing-between-systems#Vertical-spacing-between-systems
-- 
Hartmut Leister <address@hidden>