For business card scans, as long as the scanning app can scan contacts and add them to your mac then you can add them to Daylite via contact sharing.
Since Daylite does not speak to AddressBook/Contacts or Calendar out of the box. The DAV Sharing relationship must be established first. Here is a link to our Partners website as they have put together walk-through videos on how to get set up. Once you have DAV Set up, any information entered into the Daylite Group in your Contacts will constantly push information between the applications.
If you have fields or documents that you want to link, then you can add them to Daylite.