Patrik,

I have used the following to accomplish what you are asking and it has worked just fine.

1. Take your radio button component and edit the controls.  Clicking on the 'Functionality' tab go about 1/2 way down and you will see a check box for 'Post Form on Value Change'.  What this will do is when any option within this control are selected it will post back those options to the form.
2. Now, to make this easy bring a Label component onto the form.  Open the Edit components and navigate to the 'Funcationality' tab.  Goto the bottom of this tab to the 'visability' option and click on the elipse.  Select the 'Dynamic Model' radio button and then select the edit button.
3. Now within this decision model you can build the functionality to make a decision on making this lable component visable.  If you use a 'Matches' component that matches Male or Female to compare against the radio button component variable.  You will find this component under 'ThisFormData' since the variable is on this form and you have not left.  Then end components within this decision model need to be set as true and false under the mapping.
4. Now running this simple model will show the radio options.  Upon clicking on the Male or Female option the label component will display on the screen.

I have also used other style buttons which leave the form for a few seconds to look up some data and the comes back into the same form updating fields/components with the data it just gathered/processed.

I hope this helps.

Can this method be used with casading Drop Down boxes?