It's in the transition options
1) Select Transition Properties
2) Change type to Export Data to XML
3) check the boxk that says "Run for named bills of materials"
4) Select the export script to use
You'll need to make sure you already have an export script written, if you don't then you won't be able to complete this.
That is done in the admin tool under the 'Data Import/Export" selection
If you need help with that, let me know.
Retrieving data ...