XmlTree with Unicode

I am in the middle of correcting compile errors after switching to using wstring instead of string. The current non-unicode code uses the XmlTree class to parse a path value from an XML attribute. The problem is that I cannot find a wstring equivalent for getAttributeValue() so I’m a bit stuck. Is there a way of doing this? My understanding of Unicode so far is shaky to say the least, so its possible (very) that I’m misunderstanding something and would be grateful to hear what the community has to say re above?