Sending email to contact is only limited to using the native email client rather than allowing other email clients on the device.
Second sending invitation is only permisuble via sms, where email should be an option also.
Third im not sure i would need to double check here, but the option to send an email to a contact is only available if the contact has one in the profile??? But that is weird since the ovi address is needed for the contact and is already visible. Maybe this is done so the client may choose the email of choice???
It should just be automated in my opinion.