如何准确确定SPFile实例是否是转换后的文件？

I have been working on a document conversion feature for converting a docx file to a pdf file using MOSS 2007. The SPFile.Convert() call is being made in the ItemAdded event and the ItemFileConverted event is fired fine as well. The eventing seems to be working fine, but the IsConvertedFile and SourceLeafName properties of the converted SPFile instance are not always set by the conversion process. This is what I was attempting to use to determine if a call to SPFile.Convert should be made.I have been working on a document conversion fe