I think a business visa will serve your purpose - signing contract and who ur face, No work. But do not dare try to step in without a VISA else you will never ever get an entry into USA again
Citizens of many countries don't need a visa for business meetings in the US, or even to do work for a client in the US if you're employed by a foreign company. For example, I was a British citizen working in the UK for a UK company. I spent two weeks in the US working at a client telco's testing lab. I used the visa waiver program.
The airport of departure (in your home county) will check if you have a visa or ESTA authorization (for waiver country citizens) before they let you board the plane.