var xml:XML = <tag foo=".." foo2="some:some2;some3:some4....">foo2</tag>

        var retXML:XML = <a></a>;

        retXML.setName(xml.name());

        retXML.@foo = xml.@foo;

        retXML.setChildren(xml.children());

        var splitted:Array = xml.@foo2.split(";");

for each(var str:String in splitted) {

        var splitted2:Array = str.split(":");

        retXML.@[splitted2[0]] = splitted2[1];

}

trace(retXML.toXMLString());