I haven't been able to import an SVG shape into Dia. It is expecting a .shape format (see http://dia-installer.de/howto/create_shape/index.html)
One solution is to export the Dia figure as SVG and edit it in Inkscape, but I'd really like to know how to import some SVG clipart directly into Dia.
There is a way to import them but they lose quality as advanced transparency seems to be unsupported:
1) Drag and drop the SVG file into an empty drawing area.
2) Export it as .shape
:
File -> Export...
Then select "By extension" and save the file as .shape
. Then a dialog will appear. Choose the default size in there.
3) Import it:
F9 -> NEW -> SVG Shape (select the file)
That's it. If you want to import more advanced drawings, I suggest you to try different formats, for example, PNG are imported really nicely (but of course are not vectors).
Hope it helps (and I hope DIA team implements more advanced SVG support).