Create dataset in PowerBI with Rest API to Azure Analysis Services

Hi all!

I've been trying to create a dataset pointing to Azure Analysis Services via the REST API's:
Push Datasets - Datasets PostDatasetInGroup

{
"name": "ApiTestAasDataset",
"isRefreshable": false,
"isEffectiveIdentityRequired": true,
"isEffectiveIdentityRolesRequired": false,
"isOnPremGatewayRequired": false,
"datasources": [
  {
   "datasourceType": "AnalysisServices",
   "connectionDetails": {
   "server": "asazure://westeurope.asazure.windows.net/testanalysisalf:rw",
   "database": "alf"
  },
"connectionString": "Provider=MSOLAP;Data Source=asazure://westeurope.asazure.windows.net/testanalysisalf;Initial Catalog=alf;Cube=Model;User [email protected];Persist Security Info=True;Impersonation Level=Impersonate"
}
],
"tables": []
"defaultMode": "AsAzure"
}

The response it's always 400:

{
  "error": {
    "code": "FailedToDeserializeDatasetError",
    "pbi.error": {
      "code": "FailedToDeserializeDatasetError",
      "parameters": {},
      "details": [],
      "exceptionCulprit": 1
    }
  }
}

Any sugestions?

Thank you very much and best regards,

   Alfredo