OT Hyperlink help in OOo needed,please.

Hi All,

Sorry this is OT.
I am trying to figure out how to specify an address for a hyperlink in 
an OpenOffice document.
Basically I want to put a table in a document on a CD.  The Document 
will be at root level in the tree, and there will be two other folders 
at root level.  Let's say the doc is Chemicals.odt (or pdf later) and 
the folders are Tech_Appraisals and MSDS.

I have read the help in OOo on inserting hyperlinks, and I can cope 
with that bit, but my addressing is letting me down.  Say I want to 
hyperlink to a TA for Chemical number 4 in my main doc.  how do I write 
the url for a file in the folder at the same level?

eg in cell 5 of the table in the doc is a reference to Chemical #4 In 
the Tech_Appraisals folder is a TA for Chem #4 called 4.pdf

What hyperlink syntax should I use to hit that file?

ideally I would like to use buttons called TA and MSDS respectively and 
have them relate to the appropriate data.

I would really appreciate any help.

Andrew Greig
Community Distributor
OpenOffice.org
Melbourne, Australia