try adding a style metadata tag before class declaration in AS or using <Metadata> tag in MXML in your custom components:
[Style(name="borderBlinkColor", type="uint", format="Color")]
my question was about how to set an undeclared style. Hence declaring the style does not answer my question. EDIT: Besides, I never wrote that I am using custom components, but used a standard component in my example.
I hope that people don't overlook my question now that it has answers to it..
Did you try giving your button an id and setting the style in actionscript?
In a creationComplete handler:
<mx:Button id="myButton" borderBlinkColor="#ff8822" label="Test" />
@Darrell, I know I could set the styles in actionscript. I am asking for a way to do it in MXML.
Thanks anyway. Question still not answered though.. Guess its not possible..