How to make Xcode to use custom DTD for autocompletion?

Is there easy way to make Xcode to use custom DTD for autocompletion or would i开发者_StackOverflow社区t require one to write extension to the development environment to get things to work? Eclipse has support for using DTD's for autocompletion of XML files but is there similar feature in Xcode?

Structure of XML files used in our application in defined in DTD so it would be extremely helpful to get good autocomplete of all possible tags and attributes to Xcode.

I found this when searching through my filesystem:

/Developer/Library/PrivateFrameworks/DVTFoundation.framework/Resources/*.xclangspec

These files may be of interest to you.