, we normally organize the B visa paperwork and work permit applications in house and have the applicant apply for the visa outside the country. However we have not tried to convert a tourist visa to B visa before and I was looking for information on how this could be done.
The Kl embassy provides a helpful document list for B visa applications. Importantly have you original Work permit with you as well as a copy which you have signed and your contract which should show your employment for a further 90+ days.
Without the company paperwork it is 100% impossible and you would need a Thai company representative with you. Why do you think that you can no longer do a 90 day visa run for a new B visa?
It turns out that the embassy does not answer emails either since the new Brazilian staff have tried repeatedly to get a response from them. This sounds like it would be better to avoid this embassy