How to define multi-valued 'default value' parameters for a report on the ReportServer

Can someone please explain how i would define a multi-valued default parameter within the report Properties -> Parameters. I have an OLAP based report with multi-value parameters. I do not want to set the default values from within BIDS. Instead, I'd like to do this from the ReportServer (after report deployment). I have no problem when i enter a single value as a 'default value', for example:

ReportParm1 String [Deal Dim].[Shelf].&[AAM]

But, how would i define it with multiple values as a 'default value' ?, for example:

ReportParm1 String [Deal Dim].[Shelf].&[ABC] , [Deal Dim].[Shelf].&[DEF]

NOTE: It appears that you cannot use expressions, such as the 'split' function in the 'default value' space.

Any help would be greatly appreciated.

thank you.

Once you publish the report, you cannot edit the expressions that define the defaut or valid values. If you have a set of expressions in the RDL, you'll be able to choose from the evaluated values of the expressions, but you won't be able to modify the expressions themselves.

If you just want to choose from a list of values derived from expressions, put the expressions in the RDL and mark the parameter as MultiValue:

<ReportParameter Name="IntegerParam">
<DataType>Integer</DataType>
<DefaultValue>
<Values>
<Value>=(1+1)</Value>
<Value>123456</Value>
<Value>-123456</Value>
<Value>=CInt(123456/123456)</Value>
</Values>
</DefaultValue>
<MultiValue>true</MultiValue>
<Prompt>Integer</Prompt>
</ReportParameter>

If you're meaning to emit the strings representing the expressions instead of the evaluated expressions, then just make the parameter a multivalued string parameter:

<ReportParameter Name="IntegerParam">
<DataType>Integer</DataType>
<DefaultValue>
<Values>
<Value>="(1+1)"</Value>
<Value>="123456"</Value>
<Value>="-123456"</Value>
<Value>="CInt(123456/123456)"</Value>
</Values>
</DefaultValue>
<MultiValue>true</MultiValue>
<Prompt>Integer</Prompt>
</ReportParameter>

Now you can use the string value as an expression.