V150 New to zencart.
All is working well on my Zencart in testing so far but I'm a bit confused on the USPS module.... I have read the 24 pages of thread on using the latest USPS module. I have installed the 2012 verision. I have also looked at this thread...http://www.zen-cart.com/forum/showthread.php?t=176944 which deals with a similar issue, but the code did not work for me.

I am confused that I can only access USPS Priority Mail but not the USPS Priority Flat Rate Boxes that make up 98% of my shipments. Regular Priority is based on weight and get very expensive shipping from Ca to New York... so the Flat Rate Boxes are great for this.... What is confusing is all the USPS flat rate box options are availabe when using International shipping, but not domestic. This does not make sense to me.

But oddly I see in the includes/modules/shipping/usps.php file that is seems to show the boxes in the .php but they do not show up as shipping choices on zen cart....
//PRIORITY MAIL OPTIONS
if ($key == 'PRIORITY'){
$this->container = ''; // Blank, Flate Rate Envelope, or Flat Rate Box // Sm Flat Rate Box, Md Flat Rate Box and Lg Flat Rate Box

}
So my question is how do I have the medium and large flat rate boxes show up as the types of shipping choices?

Or would it just be easier NOTto use the USPS module for domestic shipping and use the FLAT RATE MODULE in ZenCart to have a flat rate shipping options for domestic shipping... For example put the variables as "if it's 6 pound or less it has a flat rate of $10.00" and if its 5-12 pounds it 14.00 etc. Im just trying to keep things as simple as possible and offer the same value as if using the USPS flat rate boxes.

Any help is appreciated.