what worked in my case is :
1) wrap the XMLA in a select as below (taking AdventureWorks for example and using variables as well):
"select
'<Create xmlns=\"http://schemas.microsoft.com/analysisservices/2003/engine\">
<ParentObject>
<DatabaseID>AdventureWorksDW2012Multidimensional-EE</DatabaseID>
<CubeID>Adventure Works</CubeID>
<MeasureGroupID>Fact Internet Sales 1</MeasureGroupID>
</ParentObject>
<ObjectDefinition>
<Partition xmlns:xsd=\"http://www.w3.org/2001/XMLSchema\" xmlns:xsi=\"http://www.w3.org/2001/XMLSchema-instance\" xmlns:ddl2=\"http://schemas.microsoft.com/analysisservices/2003/engine/2\" xmlns:ddl2_2=\"http://schemas.microsoft.com/analysisservices/2003/engine/2/2\" xmlns:ddl100_100=\"http://schemas.microsoft.com/analysisservices/2008/engine/100/100\" xmlns:ddl200=\"http://schemas.microsoft.com/analysisservices/2010/engine/200\" xmlns:ddl200_200=\"http://schemas.microsoft.com/analysisservices/2010/engine/200/200\">
<ID>Internet_Sales_"+@[User::year_recorded]+"</ID>
<Name>Internet_Sales_"+@[User::year_recorded]+"</Name>
<Source xsi:type=\"QueryBinding\">
<DataSourceID>Adventure Works DW</DataSourceID>
<QueryDefinition>SELECT [dbo].[FactInternetSales].[ProductKey],[dbo].[FactInternetSales].[OrderDateKey],[dbo].[FactInternetSales].[DueDateKey],[dbo].[FactInternetSales].[ShipDateKey], [dbo].[FactInternetSales].[CustomerKey], [dbo].[FactInternetSales].[PromotionKey],[dbo].[FactInternetSales].[CurrencyKey],[dbo].[FactInternetSales].[SalesTerritoryKey],[dbo].[FactInternetSales].[SalesOrderNumber],[dbo].[FactInternetSales].[SalesOrderLineNumber],[dbo].[FactInternetSales].[RevisionNumber],[dbo].[FactInternetSales].[OrderQuantity],[dbo].[FactInternetSales].[UnitPrice],[dbo].[FactInternetSales].[ExtendedAmount],[dbo].[FactInternetSales].[UnitPriceDiscountPct],[dbo].[FactInternetSales].[DiscountAmount],[dbo].[FactInternetSales].[ProductStandardCost],[dbo].[FactInternetSales].[TotalProductCost],[dbo].[FactInternetSales].[SalesAmount],[dbo].[FactInternetSales].[TaxAmt],[dbo].[FactInternetSales].[Freight],[dbo].[FactInternetSales].[CarrierTrackingNumber],[dbo].[FactInternetSales].[CustomerPONumber]
FROM [dbo].[FactInternetSales]
WHERE "+@[User::WHERE_clause]+"</QueryDefinition>
</Source>
<StorageMode>Molap</StorageMode>
<ProcessingMode>Regular</ProcessingMode>
<ProactiveCaching>
<SilenceInterval>-PT1S</SilenceInterval>
<Latency>-PT1S</Latency>
<SilenceOverrideInterval>-PT1S</SilenceOverrideInterval>
<ForceRebuildInterval>-PT1S</ForceRebuildInterval>
<AggregationStorage>MolapOnly</AggregationStorage>
<Source xsi:type=\"ProactiveCachingInheritedBinding\">
<NotificationTechnique>Server</NotificationTechnique>
</Source>
</ProactiveCaching>
<EstimatedRows>1013</EstimatedRows>
<AggregationDesignID>Internet Sales 1</AggregationDesignID>
</Partition>
</ObjectDefinition>
</Create>
'
as xmla"
and assign the above as string to a String variable .
2) drag in an execute SQl task and supply variable in 1) as 'SourceVariable' . Run this SQL task on a connection manager for normal transactional DB , say 'master' for instance .
3) save the 'Single Row' resultset from 2) in another String variable.
4)supply the variable from 3) to another Execute SQL task using the connection manager for SSAS cube .
hope this helps anyone landing on same ...