Reading XML attribute from a processing instruction line in C#

Platform: C#, .NET 4.5

I have the following line in a XML document

<?ish ishref="GUID-XXXXXXXXXXXXXXXXXXXX" version="1" lang="ae" srclng="en"?>

and want to read (and modify) the lang attribute. I have tried the following

newXMLDoc.Load(XMLfile);
instruction = newXMLDoc.SelectSingleNode("/processing-instruction('ish')") as XmlProcessingInstruction;

instruction returned a valid object with the innerText equal to "it's" line but I don't know how to access the attributes (tried various ways but all return null)

How do I Access the attributes of instruction (or is there another way of doing the access better) ?

PS

I have tried XPath like "/ish@lang" and instruction.Attributes but those just return NULL.

I would prefer a non LINQ solution

DS