Cannot receive incoming header DATA field

When a DATA field is received, the quickfix looks for the corresponding LENGTH field in the received fields list BUT if the LENGTH and DATA fields are part of the header, they are not found. The extractField method from the Message class should check if the LENGTH fields is a header field and search for it in the corresponding list. (Not sure what to do with the group fields though)

ex:
try {
if (group == null) {
if (isHeaderField(lengthField))

{ fieldLength = header.getInt(lengthField); }

else

{ fieldLength = getInt(lengthField); }

} else

{ fieldLength = group.getInt(lengthField); }

} catch (FieldNotFound e1)

{ throw new InvalidMessage(e1.getMessage()); }