How to change the settings of the Sheet Navigator Data Field

Hello,

I need help with the amount of Data Field spaces that MicroStation's Sheet Navigator uses to add the page numbers. For example my sheet numbering should be TCP-212, TCP-213,... but when I run the sheet navigator it always puts TCP-21,... because the maximum amount of spaces in the Data Field it uses is 6 and I need 7 spaces.

Thank you in advance.