Custom subjects in linked emails?

Hello there, I'm currently trying to build a a custom invite for an event. An RSVP has been requested, so we've created a button and linked it to an email address which automatically opens in the client when clicked. Is there anyway we can ensure this email comes with a subject line that appears in the composer box?

Thanks,
Mark

200,000 companies around the world can't be wrong.

From Australia to Zimbabwe, and everywhere in between, companies count on 
Campaign Monitor for email campaigns that drive real business results.

Get started for free
1-888-533-8098