Missing Hot keys for faster productivity

I’ve just switched from Outlook Express and although there is a lot of
good in eM I miss hot keys/accelerator keys.

People dealing with large quantities of emails benefit greatly whenever they don’t
have to use a mouse to get something activated etc.
When you write 50-100 emails per day this makes a huge difference.

For example when composing an email a hotkey to send it would be most welcome,
for example alt+s in OE. I just noticed this does work, but why not mention this in the File menu?
Such as Send alt+s where now you just have Send.

What I miss most are shortcuts for signatures. I use signatures to prepare standard responses and I like an option to insert them fast.
In OE I would just press Alt+I and than s, than I can easily scroll down with cursor keys to select the signature I want and press enter to have it inserted.
I propose you add Signatures menu item under Insert in the email composing form, this represents minimal effort for you and will be a great productivity boost for people like me.