solidworks 2003 - inserting blocks into drawing formats

I am looking for some input on the problems I am having with block insertion. I have created a custom block. I open the specified sheet format (slddrt), right click the sheet format and select edit sheet format. From the insert - block pull down I insert the custom block from the browse button. The format is saved as the original same file name, overwriting the original file. When the modified template is opened, the newly inserted block is missing. It shows up in the preview pane but not on the drawing view.

Any words of wisdom.

Thanks