Currently, we support following API for creating database with service tier/performance level:
- T-SQL
- PS cmdlets
- REST API
The level of support however differs between these APIs.
T-SQL
1. Supports specifying edition/service level only
2. Performance level will default to the lowest one for the service tier
PS cmdlet/REST API
1. Supports all options - service tiers & performance levels
Also, in current preview we support the new service tiers only on newly created servers. This means if you have existing server they will not have the ability to create new service tiers like Basic/Standard.
We are looking at relaxing these restrictions in the future. Link below has details:
http://msdn.microsoft.com/library/azure/dn369872.aspx