This is just a short note on how to configure BIDS 2008 to support OpsMgr reports development.

1. Copy Microsoft.EnterpriseManagement.Reporting.Code.dll from SSRS bin folder to C:\Program Files (x86)\Microsoft Visual Studio 9.0\Common7\IDE\PrivateAssemblies\
2. Add ManagementGroupId key to devenv.exe.config: just copy <appSettings>…</appSettings> section from your ReportingServicesService.exe.config like this:

   <configuration>
     ...
     <appSettings>
       <add key="ManagementGroupId"
         value="Your management group's GUID goes here" />
     </appSettings>
   </configuration>

3. Modify C:\Program Files (x86)\Microsoft Visual Studio 9.0\Common7\IDE\PrivateAssemblies\RSPreviewPolicy.config as follows: open file in text editor and find first <CodeGroup> element. Add this code after <IMembershipCondition> child element:

   <CodeGroup class="UnionCodeGroup" version="1" PermissionSetName="FullTrust" Name="Microsoft Operations Manager Reporting Code Assembly" Description="Grants the MOM Reporting Code assembly full trust permission.">
       <IMembershipCondition class="StrongNameMembershipCondition" version="1" PublicKeyBlob="0024000004800000940000000602000000240000525341310004000001000100B5FC90E7027F67871E773A8FDE8938C81DD402BA65B9201D60593E96C492651E889CC13F1415EBB53FAC1131AE0BD333C5EE6021672D9718EA31A8AEBD0DA0072F25D87DBA6FC90FFD598ED4DA35E44C398C454307E8E33B8426143DAEC9F596836F97C8F74750E5975C64E2189F45DEF46B2A2B1247ADC3652BF5C308055DA9" />
   </CodeGroup>

   This is how it should look after modification:

   ...
   </NamedPermissionSets>
   <CodeGroup
           class="FirstMatchCodeGroup"
           version="1"
           PermissionSetName="Nothing">
       <IMembershipCondition
               class="AllMembershipCondition"
               version="1"
       />
       <CodeGroup class="UnionCodeGroup" version="1" PermissionSetName="FullTrust" Name="Microsoft Operations Manager Reporting Code Assembly" Description="Grants the MOM Reporting Code assembly full trust permission.">
   					<IMembershipCondition class="StrongNameMembershipCondition" version="1" PublicKeyBlob="0024000004800000940000000602000000240000525341310004000001000100B5FC90E7027F67871E773A8FDE8938C81DD402BA65B9201D60593E96C492651E889CC13F1415EBB53FAC1131AE0BD333C5EE6021672D9718EA31A8AEBD0DA0072F25D87DBA6FC90FFD598ED4DA35E44C398C454307E8E33B8426143DAEC9F596836F97C8F74750E5975C64E2189F45DEF46B2A2B1247ADC3652BF5C308055DA9" />
       </CodeGroup>
   
       <CodeGroup>
   ...

That’s it! Happy coding!

PS: If you still want to use BIDS 2005, please refer this post and keep in mind that SQL Server 2005 is out of mainstream support.