Kind of "title" beetween staves

[Alberto Simões]

Hello

Although I can add manually text binding it to a note with 
^\markup{...}, how can I add an annotation to be placed exactly in the 
center of the page, between two staves?

The manual refers a "Separate Text", but it is placed between scores, 
and I would like to keep the score (it is the same music, just a note).

Thank you for any help,
Alberto