How can I select the mailbox to be displayed on the home screen on my Nokia C5 device?

When Contact bar theme is selected:

Select Menu > Settings > Personal > Home screen > E-mail notification > Mailbox.

To select Contact Bar theme perform the following:  Select Menu > Settings > Personal > Themes > Home scr. theme > Contact bar.

Applies for Nokia C5-03, C5-05, C5-06 devices.