As it turns out, DvbLink does not catch changes to service streams once a stream has already been tuned to.
Something every PVR and also WMC (native) does.
A workaround might be to allow adding individual stream pids manually e.g. to an appropriately extended channels config file.
This, BTW, could be extended to add 'option channels' e.g. as presetn in the german sky 'Budesliga, select, sport' etc.
See here for an example how this can be really disturbing:
viewtopic.php?f=56&t=25584
Please add this feature.
Thx,