ECN Forum Forums Technical Discussion Electrical Theory and Applications Meter Socket Transfer switch.

There are two US suppliers of meter adapters that may have a device to do the job.
See: http://www.marwellcorp.com/Newsltrs/ftp/news1100.pdf
also possibly: http://www.ekstrom-metering.com/cgi-bin/ekstrom-metering/vsc/cgi-bin/ekstrom-metering/group_page.cgi?U+ekstromproducts+etwn1678+5:1