[1][incomplete short citation] In the mid-1970s, Henderson studied composition with Karlheinz Stockhausen and music-theatre with Mauricio Kagel at the Cologne Musikhochschule.
Henderson's compositions include such pieces as the work for organ and pre-recorded tape, Sacred Site (1983), The Dreaming written for the Australian Chamber Orchestra, "Six Urban Songs: The Patrick White Song Cycle" for soprano and orchestra (1983), and an opera, Lindy (1997),[2] with Judith Rodriguez (as co-librettist), based on the disappearance of baby Azaria Chamberlain at Uluru in 1980.
[2] There, she continued her musical education in Germany then returned to Australia towards the end of 1976 to teach composition as a part-time lecturer at the University of Sydney.
In the mid-seventies while in Germany, she received a commission from sculptor Helfried Hagenberg to compose music on a sculpture he had created from twenty-seven triangles.
[3] She is also the inventor of the Tosca Bells, a percussion instrument with hollow metal tubes that create a vibrating bell-like sound when hit.