Hi Liska,

>a)
>How are firebird user accounts managed in such a constellation.
>Do I need one special user account (by the provider) to access a
>database from a web service application (i.e. a CGI or php)?
>How can I implement different "roles" then.
>
>

Usually, the provider will give you one (or more) user accounts.
Database is created by the provider, and you will have an alias for it.

>b)
>(How) can I access my database directly with a client application
>without a HTTP connection through a web application sitting on the server?
>
>

Some providers can give you access using ZeBeDee and private keys.
Direct connection to port 3050 is something that any provider should
give you.

>The provider is willing to make any necessary configurations but is not
>very experienced with firebird so he asked me to provide the information.
>
>

Well, you have also the chance to work with a provider that is
specialized in Firebird. :-))
Take a look at http://www.serverptbr.com

Artur