This is a feature of the CSS Sculptor tool in Design extender.
Go to WebAssist -> CSS Sculptor to begin creating your CSS Layout.
Select a layout type, then click the Edit button.
On the Box tab, select the Container you would like to add the Spry Element to, then click the plus button and select the type of spry element to add.
NOTE: You say:
Dreamweaver Spry toolkit. I am not at all impressed with the DW tools and the code they produce is difficult to trudge through to adjust the design. 
the Spry elements that are added by CSS Sculptor are the same Spry elements as are available through dreamweaver, Spry is a framework that is owned and created by Adobe.
