ID.CS3: Make Data Merge more useful?

Question

Data merge is a useful function of Indesign but its scriptability is limited. I've searched this forum and found some scripts that run a pre-linked ID document. I'm trying to script the linking of fields with known text strings.
Looking at the dictionary I see that the only thing that has read/write is properties.
My attempt to see what properties I can read/write seems to only point to its own reference.
Is this part of data merge (assignin fields to text strings) just not scriptable? thanx, sam

Answer 1

OK, here is my latest attempt to take what Olav's javascript uses and apply it to Applescript. I'm stuck on applying the myNamePlaceholder as notedby  by myNamePlaceholder:
It yields no placeholder. But I believe I've done it right because I've followed the record generated when I manually make a placeholder and get the data merge text placeholders of document 1. What am I missing?
thanx, sam
set myTextFile to ("path:to:working:date.txt") as alias --I'm using a text file that works manually.
tell application "Adobe InDesign CS3"
set {find text preferences's find what, find change text options} to {"[Sample Name]", nothing}
tell document 1
tell data merge properties
select data source data source file myTextFile
set myDataMergeProperties to properties
end tell
set allObj to (find text)
set objCt to count of allObj
repeat with thisObj from 1 to objCt
set NameObj to item thisObj of allObj
set myStory to parent of NameObj
set myFrame to parent text frames of NameObj
set NameObjOffset to item -2 of insertion points of NameObj --of myFrame
set dmFcount to count of every data merge field of data merge 1
repeat with i from 1 to dmFcount
if field name of data merge field i of data merge 1 is "FirstName" then set myNamefield to object reference of data merge field i of data merge 1
end repeat --dmFcount
set myNamePlaceholder to {story offset:NameObjOffset, field:myNamefield}
set {myNamePlaceholder} to end of data merge text placeholders
return properties of data merge text placeholders
--yields {} if I have no placeholders manually made. If I have manually made a placeholder, it yields only the manually made placeholder. What am I missing?
tell myStory
end tell
end repeat -- iterate over each instance of obj
end tell --doc1
end tell --app