I think SwishMax supports ActionScript. So try getURL() function.
I have never used SwishMax, but just tried it long ago. Flash alternatives generally provides nice effect and animations with just one click. But I prefer to use Flash instead as it provides me full actionscript support, better timeline and drawing tools and of course because Flash is the best environment for creating SWF movies. Once you get used to you barely use other.
However, creating complex effects in flash is not that easy and takes considerable time. So, the best way is to use both together. Basically you use other alternatives(like swishmax) to create individual animations. And then load it dynamically using Flash whenever required.