Do soundcards work differently regarding changing latency within sequensers?

I´m looking for an external soundcard and I´ve tried Firebox.
But I have to shut down Cubase evertime I need to change the latency.

(When I used my 3 year old soundcard Audigy I could make the changes within Cubase without shutting it down.)

My knowledge about soundcards isn´t so big. Perhaps it isn´t possible with external soundcards or ..?

I don´t know the "normal" workflow regarding this.

Could someone please enlighten me?


PS I´ve also tried within Kontakt2(standalone) and I have to shut it down also before changing.