Sibelius question - cross-clef beaming in piano parts?

Transcribing a work from fly-speck manuscript (yup - that Kernis work from Schirmer Print-on-demand . . ) and cannot for the life of me get notes alternating between the hands, between two clefs, to be on the same beam! Sibelius site down for maintenance now - and previous foray there gave me an answer that I could not understand - sounded like it might have been written by a Brit, or a non-American-terminology speaker. I am fine with unusual barring in one clef - but the piano 2 hands/2clefs/common bar thing is not working for me. Using Sibelius 5.2.5. Thanks.