I need help with QuickTips in my app.

I add some components dynamically to my app and I need to define quicktip for this component. I also need to use one background color for some quicktips and other color for other quicktips.

I've tried to create quicktips dynamically via
Ext.QuickTips.register( config );
method, however there could not be defined attribute baseCls to use another quicktip's parent CSS class.
Another way how to create quicktip is using constructor like
new Ext.QuickTip( config )[
where I can define baseCls attribute, but in spite of creating quicktip dynamically, it is not working because the initialization
is performed before creating.

So can advise me how to make it working? Thanks.