There are two keys to managing onshore-offshore relationships and ensuring an offshore team is productive. The first key is communications. Explain everything to everyone. Why is the team offshore being formed and what is expected of them. How will their progress be measured. What advantages does the offshore team have for the company and the onshore team. Explain that to both teams, onshore and offshore. The second key is maintain a presence offshore, and make them be part of the onshore team. This is hard to do properly remotely, so there's a number of techniques I've employed over the years that has greatly increased my success rate offshore.
The first step to maintaining a presence offshore, and making them feel part of the company and the onshore team, is to get over there and visit them. I try to go to my offshore teams in Vietnam, India, or wherever (although admittedly for the last few years they have been exclusively in Vietnam due to my successes there) at least once a quarter. I go for a week, which allows me to get over my jetlag, spend at least half the week and usually more in the office with the offshore team, and also get a bit of a break from the onshore office and maybe, if I'm lucky, a few days to sight-see! When visiting offshore, I try to do three things every visit. The first is to take the team out for lunch or dinner. The entire team. And let them ask any questions they want. This is a nice team-building exercise, and it helps them know me and my expectations, as well as feel as though they are more closely connected to the executives of the company. The second thing is to have a team meeting, where I present the same content to them as I show my onshore teams (edited a bit) to explain what the company is doing, what the group is trying to achieve, and how both onshore and offshore teams are working. The third thing is to meet with the leaders of the offshore team and company to explain the go-forward plans, what's happening in the future, and frankly deal with any issues that have come up.
When I have a larger team offshore, meaning at least 20 people, I try to see if any of my onshore team would like to visit the offshore team and spend a few weeks working with them. Since offshore QA is common in my groups, this usually means sending an onshore QA person to Vietnam to spend anywhere from a couple of weeks to a couple of months over there. For the employee chosen, this is both a nice little perk and a way to integrate the offshore and onshore teams. For the offshore teams, they get to talk to and work with someone who knows what is expected and how to do it far better than someone like me could ever explain, and there's a bond forms between the two quickly. For even larger teams, I try to bring one or two people from the offshore team onshore to work with the team here. The mixing of the two teams benefits both sides, and helps the two feel as though they work together much better than any number of phone calls or emails can ever do.
Sure, sending people offshore for a month is not cheap, but it also is not expensive. Consider some real numbers. An onshore QA resource may cost me $70K a year (picking a number). An offshore QA resource in Vietnam costs me $26K a year. If I have 15 people in QA offshore, I am spending $400K a year on those heads, but getting the work of 15 people instead of five people onshore (ignoring benefit costs and rounding quite a bit). Investing a few thousand dollars to ensure the $400K is wisely spent is good business practice. And a visit to a place like Vietnam is not expensive, with a total cost of less than $5K for a month. That's a good investment in the offshore process! (For the record, at time of writing, airfare to Vietnam is around $2K, a furnished, serviced apartment is about $1K a month, and a per-diem for the employee works out to about $1,500.) I like to send someone every quarter, so I spend about $20K a year sending four people to Vietnam for a total of four months a year, and the result is a much more tightly integrated team and four very happy onshore employees!
Maintaining a presence and clear, concise communications will ensure that your offshore team produces what you want, works well with the onshore team, and justifies its role in the company. And you get to save some money and increase productivity. Nice bargain.