outlook 2007 delegations tasks

I have a client that needs the following

user A needs to send user B tasks to user C

The issue is when user c accept the task the “in behave of” does not show

They have outlook 2007 sp 2

They show me in the past month it did work by showing previous tasks and stated nothing changed

I tried from my company environment and the issue replicates itself

I do have the user as delegated show and is editor is there something else I need to do ?

Thank you in advanced