A PART 135 CARGO PLT DID NOT FLY A SID DEP RTE AS ATC EXPECTED.

Narrative

I HAD FILED AN IFR FLT PLAN FROM SMX TO SBP DUE TO FOG. I WAS FILED TO UTILIZE THE BUELT 1 DEP TO FRAMS. UPON DEP; THE TWR IMMEDIATELY CLRED ME TO DEP FREQ (ZLA). THEY ACTED AS IF I WAS A SURPRISE OR AS IF THEY DID NOT HAVE MY PLAN ON FILE; EVEN THOUGH I HAD FILED; AND RECEIVED A CLRNC. APPARENTLY; THE CTLR STATED THAT I HAD NOT IN FACT; FLOWN THE COURSE HE HAD INTENDED INITIALLY. THIS STATEMENT WAS MADE ABOUT 10 MINS AFTER THE SUPPOSED 'MISNAV.' HE THOUGHT THAT I HAD NOT FLOWN TO BUELT INTXN BEFORE MY TURN ON COURSE. I THOUGHT IT STRANGE THAT EVEN THOUGH HE HAD MY XPONDER MODE C REPLY; HE FAILED TO MENTION THIS AT THE TIME. MY RECOMMENDATION IS THAT WHILE PLTS MUST DO A SATISFACTORY JOB OF NAVING UNDER IMC; CTLRS SHOULD VERIFY; WHENEVER POSSIBLE; THE COURSE OF THOSE ACFT. IF I HAD BEEN ALERTED SOONER OF MY 'OFF COURSE' I WOULD HAVE BEEN MORE THAN HAPPY TO COMPLY. ANOTHER FULLY QUALIFIED PART 135 IMC PLT WAS RIDING WITH ME (COMPANY PLT); AND HE ALSO DID NOT NOTICE ANY OFF COURSE INDICATIONS FROM THE INSTS OR CHARTS.