Outlook Addin adding custom property which can hold max number of characters

Question

I am working on a outlook 2003 addin using VSTO.Is there a way to add a custom property on ContactItem which can hold maximum number of characters, like body property of a MailItem.

Currently a custom property of type TEXT can hold max of 4000 characters. Is there a way to increase this limit or using other type of properties to overcome this limitation.