[imp] Changing Identity

[ls@lonely-star.org]

Hello Together,
I am using Horde Imp on my own webserver. Now, I have serveral eMail adresses
which I am giving to different people. When I compose an eMail it says on the
top

Identität
ls at lonely-star.org (Standardidentität)

("Stabdardidentität" means "Default Identity). How can I configure Horde Imp, so
that I have several idenities to choose from at that place?
Thanks!
Nathan