The best way to solve the problem would be to consult the archives of
Antwerp and Dendermonde, but since it sounds like you are not in a position
to do that, you might check the more expansive histories of Antwerp, like:

Mertens, F.H., Torfs, K.L., Geschiedenis van Antwerpen sedert de stichting
der stad tot onze tijden, 8 vols., Antwerp, 1845-53.

Also look into the more specific studies on the artists, like:

Straelen, J.B. van der, Jaarboek der vermaerde en kunstrijke Gilde van Sint
Lucas binnen de stad Antwerpen, Antwerp, 1855.

And since the artists' guild officially merged with the local
rederijkerkamer De Violeren in 1480, you might also check into literature on
that group:

Straelen, J.B. van der, “Geschiedenis der rederijkkamer ‘De Violieren’ of
‘Violettebloem’ onder zinspreuk ‘Wt jonsten versaemt’ te Antwerpen,” Het
Taelverbond. Tijdschrift voor geschiedenis, tael-, oudheid- en letterkunde 8
(1853), 213ff.

Straelen, J.B. van der, Geschiedenis der Antwerpse redeijkkamers, Antwerp,
1863.

Visschers, P., “Een woord over de oude rhetorijkkamers in het algemeen en
over die van Antwerpen in het bijzonder,” Belgisch museum voor de
Nederduitse tael- en letterkunde en de geschiedenis des Vaderlands 1 (1837),
137ff.

Willems, J.F., “Chronologische lijst van oorkonden, de kamers van rhetorica
te Antwerpen betreffende,” Belgisch museum voor de Nederduitse tael- en
letterkunde en de geschiedenis des Vaderlands 1 (1837), 147ff.

Much of this can be located in the US, albeit with a little work.  But your
best bet is to find a way to get to Belgium for easier access to the
literature, and for the potential to pursue your own archival research.  
It's indispensible, because the 19c historians (like any of us) were not
complete, and working to their own agendas.

Good luck, and I'm sorry that I can't supply more on Dendermonde.

--
Mark Trowbridge Ph.D.
Senior Fellow
Department of European Paintings
Metropolitan Museum of Art
New York, NY
trowbridgemhotmail.com