How can I create a new mail custom form shortcut ?

Question

Hello everyone !
It's been three hard day of searching for such a simple question:
How can I add a button to Outlook's ribbon that select a new pre-define form to send ?
I already have the button but I miss an instruction like that:
Create new mail with the form located here
Thank you in advance for helping :D
(And sorry if there is a mistake, English is not my native language)

Answer 1

Hello Dark,
private void CreateMailItem()
Outlook.MailItem mailItem = (Outlook.MailItem)
this.Application.CreateItem(Outlook.OlItemType.olMailItem);
mailItem.Subject = "This is the subject";
mailItem.To = "[email protected]";
mailItem.Body = "This is the message.";
mailItem.Importance = Outlook.OlImportance.olImportanceLow;
mailItem.Display(false);
Outlook forms are associated with items based on the message class values. To get a specific inspector window displayed you need to create an Outlook with the associated message class.
VSTO provides two different ways for customizing the Fluent UI:
1. Using the ribbon designer: Walkthrough: Creating a Custom Tab by Using the Ribbon Designer .
2. A raw XML markup: Walkthrough: Creating a Custom Tab by Using Ribbon XML