I get to do presentations quite a lot and help people with how they message around SOA and selling to the business. One of the core parts of this is how important presentation skills are and how sometimes you have to face it that you might have the content but you don't have the presentation skills. The problem is that when you don't recognise this you can find yourself hijacked by someone with better skills and thus find yourself part of their agenda rather than your own.
Bill Gates summed up this dilemma brilliantly when he did a sit down with Steve Jobs.
You want about 7:15 in when they talk about the Microsoft input into Apple II, which was around Basic. Bill starts talking acronyms and clearly trying to talk up the BASIC that he did (fair enough), Steve then steps in and reduces the Microsoft input to being just doing floating point.
The thing to think about here is that your best presenter and negotiator might not be your best architect and techy. So when you think about messaging to the business and explaining what you do think about who is best able to present that message. Have the detail guy ready to go if needed but focus on the person who can get the message across. This is an important part of an SOA journey and one skill that is often under-rated in IT.