Outlook Addin - Outlook 2016 / Outlook 365 compatible

Hello, I require an add-in for Outlook creating, using C#, that performs the following: - Adds a button on the ribbon-bar. This button, when clicked will show a drop-down button which will list a selection of White-Labels, with signatures under these. It will display as a parent / child node implementation - where they click on a parent node first, and then under and next to this will be all of the signatures. Clicking on it will then add the appropriate signature to the footer of the email. These are read from an XML file (with the signature stored in an RTF format). The XML file will list the parent white label, child signature name and child signature RTF data. A user can also choose an option of 'no signature'. - Detects whether an email is going to an internal or external receipient - If an external recipient then it will disable the send button initial until the user has choose the signature (or choose the no signature option) from the add-in. Effectively this will be used to ensure that emails are sent with the appropriate signature from staff where customers are dealt with using a variety of customer names. Thanks