Mapping emails to contacts

I’ve just started using eM Client and so far I’m pretty impressed. I have a question however. My contacts are on a carddav server (Mountain Lion) - this is working fine within Contacts. When I am looking at email I get a combination of these possibilities:

Email preview pane: the sender’s email address leads to the contact card. Skype icon is green if they are on skype
Contact details slide out tab on right: Contact details are all correct and mapped to the contact card
This is all great and how it should be.

BUT, for most of the emails I look at, when I know I have a contact card for the person, in both the preview pane and the contact details slide out tab, it doesn’t recognize that I have the contact and doesn’t map the email to the contact card. It just treats it like a suggested contact.

Any ideas on how to fix this?

It is planned for the next major version (6).