Scheduled P&L and Balance Sheet Reports with Defined Date Range

Hi
I set up a scheduled report to email out P&L and Balance sheet on a monthly basis.  However, I find that there is no way for me to define the date range.  The report that was emailed to me was the date range that was defined the last time I viewed the report on-line.

What I was trying to do was do the following :
- monthly email of YTD P&L & Balance sheet report
- monthly email of last month's P&L

Obviously, as the date moves, the date range should move dynamically as well.

Any ideas anyone?

thanks