Getting rid of extra space at the break of the line [time signature change]?

[kmg]

What is going on guys,

Thanks for your recent help, now I'm digging LilyPond more and more, but after searching in the manuals/snippets, I couldn't find how to fix this:

http://i.imgur.com/L5YCxnv.png

In this case time signature is stated in the beginning, when instrument starts solo. Then I manually re-introduce it again when piano starts it's part, so it doesn't start without signature (as previous bars of the piano are empty and hidden). Is there any way to shift the barline before the break, so it appears as normal (since time signature is invisible anyway)? I tried to change X-extent/padding of a grob, but it could only increase this space or not change it, even when I used negative values. Here's my code for this time signature change, just in case:

\version "2.19.50"
...
\once \override Staff.TimeSignature.break-visibility = ##(#f #f #t)
  \time 3/4
  c2.*2/20 \fff |

Thanks for assistance :)

Pozdrawiam,
Krzysztof Gutowski