PHP 5 XML Dom, set doctype and system

Hello, I need to set the doctype and the system dtd of a document created directly with the xml DOM. I couldn´t find any function or property to set this, i saw some examples that directly wrote onto the file manually, but i´m pretty sure thare must be a way to do this with the dom (i remembered that libxml c api has such capability, so, if php dom is based on such, then it would be able to). Any ideas? Thanks in advance, cheers. Mariano. -- No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.1.371 / Virus Database: 267.13.12/193 - Release Date: 06/12/2005