Hi Raphael,
We added "Switchboard- Callback-Mail during call" to the backlog of the Switchboard App for future development.
We can not give you any timeline if and when this will be implemented.
However I can provide you with a possible work around right now.
When using the Switchboard App, you use the myApps (Soft)Phone app in the background. With the setting to undock the Video screen in the (Soft)Phone App, you can use a small undocked Video screen with the possible call actions during a call.
By adding an external application button to the (Soft)Phone App in myApps.
You will be able to press this button on request (maybe alt tab to get the video screen on top) of the Switchboard App.
See this wiki for implementing such a button in myApps.
https://wiki.innovaphone.com/index.php?title=Howto:Integrate_External_Apps_in_innovaphone_UC_clients#Open_the_default_email_client_during_a_call_and_use_the_callinfo_in_the_email
Best regards,
Karl