centred piece titles

[Jamie Bullock]

Dear list,

Looking at the archives, this seems to have come up before, but I can't
seem to get a working solution. What is the best way to get the titles
of movements centred? At the moment I am using "\book \score \header
{ piece = "piece1"}" as outlined in the manual to seperate movements,
but of course this gives left-aligned formatting.

Thanks,

Jamie