Current wording:

NOTE: The above definition of Must Support is derived from HL7v2 concept "Required but may be empty - RE" described in HL7v2 V28_CH02B_Conformance.doc.

Comment:

It appears the reference to HL7 V28_CH02B_Conformance.doc should be a hyperlink?  

Since individual V2 chapters are in a zip file on the HL7 Standards grid, suggest providing a link to the zip file:  [HL7 Standards Product Brief - HL7 Messaging Standard Version 2.8 | HL7 International|http://www.hl7.org/implement/standards/product_brief.cfm?product_id=356]