First of all, there is no guarantee that USCIS will begin removal proceedings on a denied petition. Rarely does the agency follow up on denied petitions and begin removal proceedings. Theoretically, denied petitions should be forwarded to ICE for investigation and enforcement but this isn't the norm. So your lawyer shouldn't claim that its a certainty that you'll be in removal proceedings if your petition is denied.
I've never heard of the one year window of eligibility under CSPA. I think your lawyer was talking about the one-year appeal window of a denied petition. Regardless, read this:
http://www.ilw.com/articles/2007,0220-wheeler.shtm
It provides some additional guidance.
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I am not an immigration attorney nor do I have any experience litigating immigration cases. As always, seek professional advice before pursuing any course of action. I cannot be held accountable for any consequences of my comments.