The sample 'Make Sang Red' from here:
http://www.sketchucation.com/forums/scf/viewtopic.php?f=180&t=17888&p=145120&hilit=Make+Sang+Red#p145120
might help:
# Add a new configurable option to Sang.
# (Any attribute that starts with an underscore
# is a "meta attribute" that describes behavior.)
sang_def.set_attribute 'dynamic_attributes',
'weight', '145'
sang_def.set_attribute 'dynamic_attributes',
'_weight_label', 'weight'
sang_def.set_attribute 'dynamic_attributes',
'_weight_formlabel', 'My Weight'
sang_def.set_attribute 'dynamic_attributes',
'_weight_units', 'STRING'
sang_def.set_attribute 'dynamic_attributes',
'_weight_access', 'TEXTBOX'
Not sure if this would enough to make a normal component into a DC!
Will try.