adding a staff system for a few measures to a piano

Hello all,

I thought this topic had been discussed before, but I was either unable to find it back or I have been imagining it.

Anyway, for a couple of bars my piano needs three staffs to clearify the writing. Afterwards it can go back to the normal two staffs. Hence my question of course ... how do I add a thrid staffsystem on a temporary basis which disappears as of the next line.

Once again, many thanks in advace.

WS

On what?

Hello,

Sorry for my oversight.... I forgot to mention that the program I use is Finale 2009.

Thanks in advance,

WS