You can try this:
java -jar jpos.jar -c "smconsole -lmk /tmp/my.lmk -rebuildlmk; shutdown --force"
It will create a /tmp/my.lmk file that will look like this (please note values are random and change from call to call)
#Local Master Keys
#Tue Oct 27 09:08:16 UYST 2009
LMK0x01=1337EA1938F43D98F740D9F819707CBF1337EA1938F43D98
LMK0x00=790E4F5B833D043B2575CD4AFE197C02790E4F5B833D043B
LMK0x09=5D5D8A19251032A12570167A1ABF629D5D5D8A19251032A1
LMK0x08=2FE601BF4034499D31983B04949BCBE52FE601BF4034499D
LMK0x0e=DCDC43454F8CC48AE03DBCA462BC752ADCDC43454F8CC48A
LMK0x07=4C645EC79279589E16F7E91AFB61D64C4C645EC79279589E
LMK0x0d=C4F4DFDF7F9737CED03B165854D6C7B6C4F4DFDF7F9737CE
LMK0x06=BFB9526D83373DA21C0D57BC91BFB3BCBFB9526D83373DA2
LMK0x0c=62C11A134502CBF852B654E997C7610762C11A134502CBF8
LMK0x05=E0E637EA463725522FB967D579389EC7E0E637EA46372552
LMK0x0b=98BA67DFEA611926AE70D6FB4F3E1F2998BA67DFEA611926
LMK0x04=A7B0CB5746021AF1CEA829E901AB3EA2A7B0CB5746021AF1
LMK0x0a=26C4B06EA8AE1534347F92A432544C1326C4B06EA8AE1534
LMK0x03=E3767FF8897AEC70C2430E68EC73371CE3767FF8897AEC70
LMK0x02=7CB30EB310A4E052D661019DD9E983327CB30EB310A4E052