Troubles in the transition DO to Ventilated heat oven

Hi everyone, 

I ve been making sourdough bread since 2 years now, I move with my girlfriend to the Sao Paulo coast in Brazil, a wonderful place of nature ! Here we would like to create a small bussiness of Artisan bread delivery in the morning ( about 20 customers not more). The problems is that we used to bake our bread in a Dutch Oven, we had some really amazing bread, well scored, lovely crispy crust, etc..  But we wanted more and we bought a Oven with "ventilated heat"as we want to create our mini bussiness ( bread, viennoisserie, etc). 

We are now in a Test phase, were out of the 6 bread we baked just 1 was good ( but nothing close to the bread we cooked in a Dutch oven). We tried various method and temperature, the oven has steam funcion that would distribute steam during a determined time (in second). It came also with a pizza stone.

The results are really sad... The crust not so crispy,we never managed to score properly yet, some of the bread are not really baked in the inside, and I already miss the various hole that we had in a slice of DO bread...

Is there anyone who has been through this transition and get great sucess ? 

PS: sorry for my English folks 

I would like to thanks everyone that could help us.

Thank you, Merci, Obrigado