getResponseAttachmentAttr
Returns the value of a given attribute of a part in a multipart response.
General format
void getResponseAttachmentAttr( id, attrName, attrValue )
Syntax rules
1. id, attrName and attrValue are alphanumeric data items.
General rules
1. id can be extracted from the list returned by getResponseAttachmentIDs while attrName can be extracted from the list returned by getResponseAttachmentAttrNames.
2. attrValue receives the attribute value.