Hi GAM,

> Anyway, the issues I was experiencing are:
> 1. Parcel quoted when weight and dimensions < Large Letter
> maximums.
> 2. iirc, a single item <9cm x 9cm x 1.5cm returns 'at least one
> dimension is invalid' and also, iirc, > above but < max. letter
> returns '...max. girth exceeded...' or similar error msg.
> 3. Specifying the mentioned 50mm x 50mm x 30mm didn't
> work either.

> I looked at tricking the 'stack' method by specifying 0.5cm and
> 9x9cm so that it would accept Large Letter for 4x product of this
> size. It didn't work, iirc, max girth msg.

To fix this, load /includes/modules/shipping/austpost.php into a text editor.

Look for the line that reads:
if ($dest_country == "AU" ) {

Then immediately before this line add the following:
----------------------------------------------------------------------
$var = array($swidth, $slength, $sheight) ;
sort($var) ;
if ($var[0] < 50 { $var[0] = 50 ;}
if ($var[1] < 50 { $var[1] = 50 ;}
if ($var[2] < 50 { $var[2] = 50 ;}
-------------------------------------------------------

This should fix those errors.

> Also, if you can explain or point me in the right direction on how to > enable/disable debugging this would be a great help as I would like > to try some things out and offer any assistance if I can.

Somewhere around line 96 of the file mentioned above you should find a line that contains "debug = 0". Change this to "debug = 1".
Note: The output isn't particularly pretty and you may not find it'll give all the information you need. Give it a go though.

BTW, when it comes to letter rates, the austpost server doesn't get contacted at all. The rates for these are predefined in the config options. The Austpost server will only quote for parcels, which is why it produces errors when it gets fed data that is considered 'too small' to be a parcel.

Cheers
Rod