As you know, Corel DESIGNER is a product specifically built for technical illustration, based on a common engine with CorelDRAW. One of the many features that sets Corel DESIGNER apart from CorelDRAW and other "creative illustration" packages is the Enhanced Line Styles that enable users to better document their graphics. While the user interface does not offer an option to customize the enhanced line styles, Claude who is part of the development team just posted a detailled article about this in the CorelDRAW Insider blog. If you use DESIGNER and/or need to customize your line styles, this is well worth a read:

http://community.coreldraw.com/blogs/insider/pages/how-to-create-custom-outline-enhanced-pattern-style.aspx