spacing markups between scores

[VSD]

does anybody how to override the vertical space in markups between scores  
inside a \book block?

I want to change the separation between the text and the staff. I'm  
looking for something like:

\override TextScript #'staff-padding = #0.2

or

\override TextScript #'padding = #0.2

but this doesn't work in the following example:

%%%%%%%%%%%%%%%%

\version "2.6.0"

\book
{
  \override TextScript #'staff-padding = #0.2

  \markup "hello 1"

  \score
  {
    \new Staff
    {
      a' b' c' d' e' f' g' a'
    }
  }
        
  \markup "hello 2"
        
  \score
  {
    \new Staff
    {
      a' b' c' d' e' f' g' a'
    }
  }
}

%%%%%%% EOF

Setting aftertitlespace in a \paper block alters the separation but it  
does it up to a minimum (with aftertitlespace = 0\mm) I would like to  
decrease it further. And this also affects to the space after the title,  
and I would like to have different values for each thing.

Any hint?

Thx,

Vincent