Shared virtual environments (SVEs) have been researched extensively within the fields of education, entertainment, work, and training, yet there has been limited research on the creative and collaborative aspects of interactivity in SVEs. The important role that creativity and collaboration play in human society raises the question of the way that virtual working spaces might be designed to support collaborative creativity in SVEs. In this paper, we outline an SVE named LeMo, which allows two people to collaboratively create a short loop of music together. Then we present a study of LeMo, in which 52 users composed music in pairs using four different virtual working space configurations. Key findings indicated by results include: (i) Providing personal space is an effective way to support collaborative creativity in SVEs, (ii) personal spaces with a fluid light-weight boundary could provide enough support, worked better and was preferable to ones with rigid boundaries and (iii) a configuration that provides a movable personal space was preferred to one that provided no mobility. Following these findings, five corresponding design implications for shared virtual environments focusing on supporting collaborative creativity are given and conclusions are made.