Positioning of half rests

[Karenee Herman]

I'm fairly new to Lily Pond, and I've been trying to get a half rest to center in it's space - as in, a half rest version of entering R1, where the whole rest centers in the measure.  There doesn't seem to be any info on it in the manuals or the mailing-list archive.  Does anyone know how to do this?

Here's an excerpt of what I have:

\version "2.12.2"

upper = \relative c'' {
    \clef treble
    \key f \major
    \time 4/4
    d2 c
    r2 r4 g8 a }

lower = \relative c' {
    \clef treble
    \key f \major
    \time 4/4
    f,8 d' g a bes2
    f,8 d' g a bes2 }

\score {
    \new PianoStaff <<
        \set PianoStaff.instrumentName = #"Piano "
        \new Staff = "upper" \upper
        \new Staff = "lower" \lower
        >>
    \layout { }
    \midi { }
}

I've attached the PDF.  In the second measure, I need the half rest to center over the eighth notes, as opposed to aligning to the left like a half note.  Hope this makes sense, and that someone can help!

Thanks,

Karenee Herman

Lullaby.pdf
Description: Adobe PDF document