Whoops - left out an important piece of the rules
header __RCVD_IN_JMFILTER
eval:check_rbl('JMFILTER','hostkarma.junkemailfilter.com.')
describe __RCVD_IN_JMFILTER Sender listed in JMFILTER
tflags __RCVD_IN_JMFILTER net
header RCVD_IN_JMFILTER_W eval:check_rbl_sub('JMFILTER', '127.0.0.1')
describe RCVD_IN_JMFILTER_W Sender listed in JMFILTER-WHITE
tflags RCVD_IN_JMFILTER_W net nice
score RCVD_IN_JMFILTER_W -5
header RCVD_IN_JMFILTER_B eval:check_rbl_sub('JMFILTER', '127.0.0.2')
describe RCVD_IN_JMFILTER_B Sender listed in JMFILTER-BLACK
tflags RCVD_IN_JMFILTER_B net
score RCVD_IN_JMFILTER_B 4.0