I wiil have to agree with Dwayne.
If you want to have a seamless sync in Lectora you will have to import the sound files as wavs and add events within Lectora Audio editor and show/hide everything you need. Then as you publish your content and choose the audio and image compression all wavs will be converted to flvs.
If you are using an animation like .swf or .gif it's best that you embed your sounds and everything else in the animation files and have them synced before importing them to Lectora.
Or if you are a Flash expert you can probably use the Flash command actions of Lectora that talk to Letora objects and back. I cannot help there, but I think a little digging in that direction might help you solve your problem.
