I hacked this before in ./packages/acs-tcl/tcl/text-html-procs.tcl in version 4.6 to allow all HTML to be posted on the forums:
diff text-html-procs.tcl text-html-procs.tcl~
596,597c596
< #set tagname [string tolower [string range $html [lindex $name_idx 0] [lindex $name_idx 1]]]
< set tagname "li"
---
<blockquote> set tagname [string tolower [string range $html [lindex $name_idx 0] [lindex $name_idx 1]]]
</blockquote>
615,616c614
< #set attr_name [lindex $attribute 0]
< set attr_name "href"
---
<blockquote> set attr_name [lindex $attribute 0]
</blockquote>
