Agree with this 100%. Setting up a Company (especially with a foreigner involved) is not an easy process, and not something a thai business man would be able to do, therefore a lawyer is really the only entity that can do this for you correctly. Also you must research this before going ahead, as to preferential/non preferential shares, other shareholders/director, voting rights, tax implications, Accountant etc.
Also most importantly who will be the person that actually has the authority to transfer the land at the land Office (as a foreigner you cannot), so the company and its assets, will be wholly owned by them, for the duration of the land transfer....There are many pitfalls with having a Thai Company, so beware. It is also a time consuming process.