I would probably rather push if I can.
But, I don't know enough to even know what custom document properties are.
Can you enlighten me.

Basically I have 8 fields in an excel sheet that I want to end up in the word document.

The word document is quite complex with 3 sections, 2 have headers which need this excel info, but the other ones doesn't. Up until now this form has been used with the headers being populated with content controls and the toolkit replicating these in the various places. The size of the document can also vary depending on how much detail is entered as each table could possibly expand over multiple pages.

These documents have been in place for a while, but have required entering the header info 12 times (one for each form) when this info is already on a spreadsheet.

Therefore I want them to be able to open the spreadsheet, enter the details then click on a button to open the word document, which then takes some info from the spreadsheet.

It was all working fine until I tried to put spreadsheet details in the word header.

Any help would be great, thanks.