1.There is description about data center where our servers are held. I think its possible also to get certificate copy from them if that's needed.
For more information see
Dattum data center.
2. Data backups - we make backups to mirror server each 24h, its is also possible to give DB copies to you. We use https for secure connection, also production SQL servers are not the same where is Skybill, so it is normally not possible to access data without appropriate link and passwords, this is Microsoft technology, not ours.
3. From firewalls point of view there are 2 levels, 1 is from Data center - protections against D-DOS attacks etc. other is our own, will not mention them there for security reason.
4. It is always possible to set up all this on some other server (but it can take some 1-2 day setup time)