How do I access the 1 button combos?

[SamSmoot]

The one example of this I've noticed on NIN is that Bunshin, when executed, tuned into Phantom Kamaitachi. It still does, but there's now an option to split the two into separate buttons. Not much of a change.

I was hoping for something like WoW's castsequence macro command which let you chain any number of actions onto one button.