Clock Manager DST not working??

sling100

For ages I've used a version of the old axcess system call to deal with DST issues when the processor has no external timeserver access (which is most of my commercial systems). As it's now 2014, not 1994, I thought I'd update the routine using the CLKMGR internal functions. All is good (even worked out that sending occurrence '5' = last), however I cannot get the DST function work at all - even if I set it in the web interface. All of the settings seem to be correct (and polling them in code confirms this), but it gets to the prescribed time and just ticks over - nothing happens. I've tried both 4.1 and 3.60 firmware as I read about a potential bug, but no dice.

Anyone got any pointers here? I'm clearly missing something fundamental, just not sure what .....

Simon