The Spare_Part_Price_List.pdf file was initially attached to the Time Machine User Guide Ftmap and given the spare_parts originId.
The Time Machine Configuration Guide Ftmap already has the time_machine_drawing.png file attached to it.
It is possible to add the Spare_Part_Price_List.pdf to the Time Machine Configuration Guide Ftmap as follows:
<?xml version='1.0' encoding='utf-8'?>
<controlFile>
<resources>
<resource>
<originId>time_machine_configuration_guide</originId>
<attachments>
<attachment>
<originId>spare_parts</originId>
</attachment>
</attachments>
</resource>
</resources>
</controlFile>