Agree with Chris (Above).
Here's my 1-2-3.
1. A warm intro is brilliant - especially from a company they funded before OR missed out on that did darn well.
2. Keep answers short, but loaded to enlist questioning from them. This creates a discussion rather than a bombardment. Ask them questions and let them discover the answers about your product by leading them in.
3. Don't pitch a VC - pitch a partner who understands the opportunity and has taken a stake in something similar or ancillary.