How to stop emails in 8707?

I'm travelling overseas next week. So to avoid high roaming charges in relation to data download, I want to stop my blackberry to receive any email messages.
To try this out, I went to the setting 'send email to handheld' and changed it to 'No'. Now I have stopped receiving any email messages, but when I set the setting back to 'Yes', I dont receive the old emails which were sent to me during the period the setting was 'No'.

How do I get all my old emails in my blackberry when I synchronise with Outlook?

Thanks in anticipation.
:)