The default vlan is based on the media type, eg ethernet's default is 1, TR is 1003. On a CatOS switch I believe you could enter "set vlan 11 name default type ethernet mtu 1500 said 100011 ...." and on an IOS switch not sure it will work for the default vlans but you could try "vlan 11 name default media ethernet state active said 100011 mtu 1500". See link:
http://www.cisco.com/en/US/products/hw/switches/ps646/products_command_reference_chapter09186a008007d830.html#xtocid67744
Hope it helps.
Steve