Microsoft has updated its support documentation for virtualised communications clients. New scenarios include:
Office Communicator 2005 supports Terminal Services and Citrix MetaFrame only when Office Communicator is used for text chats and presence functions.
Office Communicator 2007 supports Terminal Services and Citrix MetaFrame when Office Communicator is used for text chats, presence functions, and Remote Call Control (RCC) functions.
Office Communicator 2007 R2 supports Terminal Services and Citrix MetaFrame when Office Communicator is used for text chats, presence functions, desktop sharing, and Remote Call Control (RCC) functions.
Office Live Meeting 2007 supports Terminal Services and Citrix MetaFrame for Web conferencing functions.
Source: here