In case you need to use 2008 Report Designer (SQL Server Business Intelligence Development Studio which comes with SQL2008 Reporting Services), please add the following configuration string close to the end end of RSPreviewPolicy.config file.
<CodeGroup class="UnionCodeGroup" version="1" PermissionSetName="FullTrust" Name="Aspose.Pdf_for_Reporting_Services" Description="This code group grants full trust to the Aspose.Pdf for Reporting Services assembly.">
<IMembershipCondition class="StrongNameMembershipCondition" version="1" PublicKeyBlob="00240000048000009400000006020000002400005253413100040000010001000734cc24bfcebd7aa8c6e2bf8af5c2b95c7a7e6092abb60d68a7d9efde285cf7dce7f354b44cf3064e8ad85bddfe405ad1e51855d9a1367c15cb34529988feeee0c3279caecdb6dfd7f94c5364d2bd282c4f93493d56d33df36f97da8fd71bb7dc4b0e7f1428b926291cdea7cec1085aa9cc0f6771e4fc2f5772603eee3afaaa" />
Please note that the configuration information will be added before the following tags appear. Please note that the instructions are similar as specified over Install to Report Server except for the file names to be changed and their respective location (The above link shows information on how to update the SQL Report Server configuration files).
Please add the following information in RSReportDesigner.config file.
<Extension Name="APPDF" Type="Aspose.Pdf.ReportingServices.Renderer,Aspose.Pdf.ReportingServices" />
The above information will be added under <Render> which itself comes under <Extensions> tag. Please take a look over following link which explains the details regarding these steps Install to Report Server. In case you still face any problem or you have any further query, please feel free to contact. We are really sorry for your inconvenience.