I was working with the PSAProjInvoice and was struggling with getting the form notes for the invoice to work, so I went and added a new field for this.
Here is the process:
1. Go to the table PSAProjInvoiceHeaderTmp and add a new field:
Save the table.
2. Go to the class called PSAProjInvoiceDP and edit the “insertPsaProjInvoiceHeaderTmp” method. Add this line of code:
tmpPSAProjInvoiceHeader.FormLetterTxt = FormLetterRemarks::find(projInvoiceJour.LanguageId,FormTextType::ProjectInvoice).Txt;
Save and compile the class.
3. Open the report in Visual Studio and refresh the dataset (PSAProjInvoiceHeaderDS). The new field should now be visible in the dataset. Add the new field into an expression in the report, save and deploy.
Take a look at this blog post for more information on how to edit existing SSRS reports in AX2012.