[TxMt] Setting the filename of a new file

[Quentin Stafford-Fraser]

I'm using TextMate to keep my daily log book - I have a
'Journal' template, language and snippets and it all works 
very nicely.

What I'd really like is that when I create a new file from 
the template, it immediately gets a filename based  on 
the date - eg. 060418.txt - so I don't have to enter that 
manually when I go to save it.

The template creates the new file in the usual way, by 
copying some standard contents to $TM_NEW_FILE.  
I was hoping that I might then be able to call osascript 
and do something like

  tell application "TextMate" to save the document 
      of front window in "060418.txt"

but it doesn't seem to work.

Any suggestions most welcome!