old_contents: from django.conf import settings
  from django.utils.translation import ugettext_lazy as _
  from satchmo.configuration import *
  from satchmo.utils import is_string_like, load_module
  TAX_GROUP = ConfigurationGroup('TAX', _('Tax Settings'))
  TAX_MODULE = config_register(StringValue(TAX_GROUP,
      'MODULE',
      description=_("Active tax module"),
      help_text=_("Select a module, save and reload to set any module-specific settings."),
      default="satchmo.tax.modules.no",
      choices=[('satchmo.tax.modules.no', _('No Tax')),
      ]
  ))
  DEFAULT_VIEW_TAX = config_register(BooleanValue(TAX_GROUP,
      'DEFAULT_VIEW_TAX',
      description=_("Show with tax included"),
      help_text=_("If yes, then all products and the cart will display with tax included."),
      default=False
  ))
  
  # --- Load default tax modules.  Ignore import errors, user may have deleted them. ---
  _default_modules = ('percent','area')
  for module in _default_modules:
      try:
          load_module("satchmo.tax.modules.%s.config" % module)
      except ImportError, ie:
          log.debug('Could not load default tax module configuration: %s\n%s', module, ie)
  
      
  # --- Load any extra tax modules. ---
  extra_tax = getattr(settings, 'CUSTOM_TAX_MODULES', ())
  for extra in extra_tax:
      try:
          load_module("%s.config" % extra)
      except ImportError:
          log.warn('Could not load tax module configuration: %s' % extra)
  
new_contents: from django.conf import settings
  from django.utils.translation import ugettext_lazy as _
  from satchmo.configuration import *
  from satchmo.utils import is_string_like, load_module
  from satchmo.shop import get_satchmo_setting
  
  TAX_GROUP = ConfigurationGroup('TAX', _('Tax Settings'))
  TAX_MODULE = config_register(StringValue(TAX_GROUP,
      'MODULE',
      description=_("Active tax module"),
      help_text=_("Select a module, save and reload to set any module-specific settings."),
      default="satchmo.tax.modules.no",
      choices=[('satchmo.tax.modules.no', _('No Tax')),
      ]
  ))
  DEFAULT_VIEW_TAX = config_register(BooleanValue(TAX_GROUP,
      'DEFAULT_VIEW_TAX',
      description=_("Show with tax included"),
      help_text=_("If yes, then all products and the cart will display with tax included."),
      default=False
  ))
  
  # --- Load default tax modules.  Ignore import errors, user may have deleted them. ---
  _default_modules = ('percent','area')
  for module in _default_modules:
      try:
          load_module("satchmo.tax.modules.%s.config" % module)
      except ImportError, ie:
          log.debug('Could not load default tax module configuration: %s\n%s', module, ie)
  
      
  # --- Load any extra tax modules. ---
  extra_tax = get_satchmo_setting('CUSTOM_TAX_MODULES')
  for extra in extra_tax:
      try:
          load_module("%s.config" % extra)
      except ImportError:
          log.warn('Could not load tax module configuration: %s' % extra)
  
subject: add back support for custom tax modules, closes #509