The Brazilian delegation to the BRM had asked for a mapping from the legacy Microsoft formats to their OOXML counterparts to be included in the standard specification, as providing this backwards compatibility is one of the main selling points of the standard:
This person tried in saying that believes that we should not submit our proposal that asked the mapping, since there was no time at the meeting (just over three hours) to write the mapping document. We’ve said that our proposal stemmed from the premise that the ECMA had this document because they justifies "the need" of OOXML because it supports the binary documents legacy and it is also stated that there are still things that can not be translated (deprecated), they should have thoroughly studied this and at least have made the mapping.
I have never seen a person so nervous and ashamed in my life... He said that Microsoft should have this mapping and if we want, we can ask it to Microsoft but not ask it to ECMA. He said that ECMA was only responsible for creating the new XML schema and who do not have this mapping documentation.
He was urged not to pursue this proposal by an ECMA member, who cited time constraints. When pressed, the ECMA representative admitted that the organization (which is responsible for the submission of OOXML) has no clue how to map legacy formats to the newly proposed ones and thus a major part of the standard is only known to Microsoft and not available for any possible independent implementors.