CentOS - Apr 2013 - C5-C6 Migration problem: HTML-Formatted email in Squirrelmail disappears

Greetings,

In Squirrelmail, you can install a plugin html_mail, that allows you to 
compose html-formatted email.

This plugin functions with Firefox and Internet Explorer; it doesn't 
function in Google Chrome.

In CentOS 5 with PHP5.1, I could copy and paste  html-formatted text 
with complicated html (tables, css, etc) from a text editor into the the 
html-formatting pane of squirrelmail, and the message would be delivered 
as html-formatted to the recipients.

In CentOS 6, with PHP5.3, using Squirrelmail with the html_mail plugin, 
copying html-formatted text from a text editor into the html-window in 
Squirrelmail, the delivered email only shows the header information.

Using pine, I see that there is an attachment, viewing the attachment, I 
see the original html code that was composed in a text editor.

Viewing this same received email in a web-based client (Gmail or 
Squirrelmail), all of html-formatting disappears.

Any suggestions on how to troubleshoot and resolve this?

Much thanks.

Max Pyziur
pyz at brama.com