Look up EA9CD's detailed information on QRZ ... you will find in his details the following:
QSL CARD ONLY VIA DIRECT IN MODE DIGITAL (NO BUREAU)
And on his webpage at http://www.ea9cd.com/ ... "Confirmation of QSL in ways digital single direct road SATSE (2 $, 1 IRC or 2 Euro) "
So he is quite clear about the qsl method for digital... I had a psk qso with him on Aug 8, 01 and received his card Oct 5, 01.
I periodically upload my log to eqsl ... did not think to exclude this qso and later noticed the rejection.