Can I enforce the order of XML attributes using a schema?

Our C++ application reads configuration data from XML files that look something like this:

<data>
    <value id="FOO1" name="foo1" size="10" description="the foo" .../>
    <value id="FOO2" name="foo2" size="10" description="the other foo" .../>
...
    <value id="FOO300" name="foo300" size="10" description="the last foo" .../>
</data>

The complete application configuration consist of ~2500 of these XML files (which translates into more than 1.5 million key/value attribute pairs). The XML files come from many different sources/teams and are validated against a schema. However, sometimes the <value/> nodes look like this:

<value name="bar1" id="BAR1" description="the bar" size="20" ... />

or this:

<value id="BAT1" description="the bat" name="bat1"  size="25" ... />

To make this process fast, we are using Expat to parse the XML documents. Expat exposes the attributes as an array - like this:

void ExpatParser::StartElement(const XML_Char* name, const XML_Char** atts)
{
 // The attributes are stored in an array of XML_Char* where:
 //  the nth element is the 'key'
 //  the n+1 element is the value
 //  the final element is NULL
 for (int i = 0; atts[i]; i += 2) 
 {
  std::string key = atts[i];
  std::string value = atts[i + 1];
  ProcessAttribute (key, value);
 }
}

This puts all the responsibility onto our ProcessAttribute() function to read the 'key' an