[Typo3] backenduser shoule write email

[toni]

hello,
is there a possibility to give BE-USER a kind of
email center, thus they can write other BE-Users emails.

I tried to install sys_messages. But this is leading to a error message.
it seems that sys_messages is not compatible with typo 3.8.0 - or buggy 
in any way.

cheers - toni