The biggest thing to consider will be the relationship between the two teams. Will it be complimentary or competitive? If competitive, what will be the incentives for both sides to drive sales to the next level? If complimentary, how will the teams divide the responsibility of who cares for what part of the sales process?
If you ask field sales about being on board with inside sales, they're likely to say, "We don't need anyone inside. We are feet on the street -- there is no other way." Meanwhile, inside sales will be eager for phone sales, as well as follow ups for leads generated online and inbound.
Your biggest sale to the field team will be that the more sales you can get (with their participation, of course) the more that can be earned and the bigger the bonus programs can be.
Sometimes you'll have to go through the "forming, storming, norming and performing" management scenario where you'll get some resistance and then eventually everyone gets it and just moves onward toward sales goals.
Keep in mind how much can be produced by outside versus inside, and there may be a need to cross train so that both sides can help each other in closing deals. What the outside team sees, the inside may not, and vice versa. You'll need to show them what it means to stay in contact and help each other understand more of what's going on in the customers mind.
It isn't just about adding sales. It's about adding value to the team and each individual as well.
Related: Build a Stellar Sales Team
Related: How Entrepreneurs Can Conquer Fear of Selling