In ODF 1.2 CD02 REV01, section 1.4.2.4, the conformance clause (D4.4) contains the OpenFormula namespace URI "urn:oasis:names:tc:opendocument:xmlns:openformula:1.0".
This is the incorrect URI. The TC had in its meeting on June, the 2nd 2008 agreed that namespace URI shall be
"urn:oasis:names:tc:opendocument:xmlns:of:1.2"
See
http://lists.oasis-open.org/archives/office/200806/msg00024.html
http://lists.oasis-open.org/archives/office/200804/msg00024.html