The Dashes.. dialog in Claris CAD can only display 6 dash patterns at once. However, you can have more than 6 patterns in your documents:
1) You can draw using the 6 dash patterns in the dialog, then change the patterns in thedialog and create new lines. (The dash patterns of the lines that you have already drawn will not change.)
or
2) You can use the Line Style floater (choose Show Line Styles under the Pen menu) to create many line styles with a different dash pattern for each style if you wish.