I just conducted a workshop in Kansas City for the AAAA on presenting creative work. It was a full house with people from all over the mid-west. The big takeaway for most of the people in the room was ..."Remember, you are solving a business problem, not a creative problem." This means that the greater the business credibility that the creative staff has during the presentation, the more likely the client/prospect is to accept your solution.
Something as simple as reiterating the strategy prior to showing the creative work can help to establish the creative staff's credibility. I understand that it is likely that the planner or account person just presented the strategy, and it may seem redundant for you to do a brief summary of the strategy. Recognize you are doing this brief summary of the strategy to show that YOU understand the strategy.
I am a big believer that in the creative world countless hours are wasted reworking creative not because the creative needed reworking, but because the client didn't "get it." I am a big fan of getting ideas accepted more quickly so do whatever it takes to get that to happen.