Hi Ben, not sure what you mean by "from the channel store itself". Generally when a home page ad launches a channel it does include contentID as a URL parameter. If the channel is not installed I believe it takes you to the channel store where you can add the channel, and I believe but am not 100% certain that the url parameters are passed along.
If you mean launching it via your own Curl script
curl -i -d ""
http://10.8.5.213:8060/launch/11?contentID=<channelID>
or using asyncPostFromString, then I think you can't send URL params along to the channel unless it is already installed, as this feature was not implemented.
- Joel