MDX Query With Parameter Using OleDb?

I posted this question on the Analysis Services forum ( http://forums.microsoft.com/MSDN/ShowPost.aspx?PostID=1087288&SiteID=1 ) and Irina asked me to post it over here to get an answer.

I'm trying to run an MDX query against SSAS2005 with a parameter. It works fine with ADOMD.NET, but I can't get it to work using OleDb. (I have to use OleDb because of limitations of the calling application.) Is this possible?

The following code works:
//using Microsoft.AnalysisServices.AdomdClient;

string MDX = "with member [Measures].[Test] as Str(@Param1) "
+ "SELECT [Measures].[Test] on 0, "
+ "[Product].[Category].[Category].Members on 1 "
+ "from [Adventure Works]";

AdomdConnection conn = new AdomdConnection("Provider=MSOLAP.3;Data Source=localhost;Initial Catalog=Adventure Works DW;Integrated Security=SSPI;Persist Security Info=false;");
conn.Open();
AdomdCommand cmd = new AdomdCommand(MDX, conn);
cmd.Parameters.Add("Param1", "abcde");
System.Data.DataSet ds = new System.Data.DataSet();
AdomdDataAdapter adp = new AdomdDataAdapter(cmd);
adp.Fill(ds);
Console.WriteLine(ds.Tables[0].Rows[0][1]);
conn.Close();

The following code fails:
//using System.Data.OleDb;
string MDX = "with member [Measures].[Test] as Str(@Param1) "
+ "SELECT [Measures].[Test] on 0, "
+ "[Product].[Category].[Category].Members on 1 "
+ "from [Adventure Works]";
OleDbConnection conn = new OleDbConnection("Provider=MSOLAP.3;Data Source=localhost;Initial Catalog=Adventure Works DW;Integrated Security=SSPI;Persist Security Info=false;");
conn.Open();
OleDbCommand cmd = new OleDbCommand(MDX, conn);
cmd.Parameters.AddWithValue("Param1", "abcde"); //changing it to @Param1 doesn't help
System.Data.DataSet ds = new System.Data.DataSet();
OleDbDataAdapter adp = new OleDbDataAdapter(cmd);
adp.Fill(ds); //produces error: "The following system error occurred: The parameter is incorrect. . Error Code = 0x80070057, External Code = 0x00000000:."
Console.WriteLine(ds.Tables[0].Rows[0][1]);
conn.Close();