how to set default option for a combo box.

I want a default option set from the list of options. In a regular select object this is done w/ the selected attribute of the option tag. So instead of a blank line showing when the combo box is built I want a default option listed there.

Probably, you have got the answer by e-mail, but...

In case of initialization from html select you can use "selected":
 
...
 
If combo is initialized from xml, you should set "selected" attribute with "1" as a value:
 
...