为什么我的CRM工作流程步骤单独运行，但不存在两个步骤？

I have created a custom workflow activity that copies attachments from a case to an email, both supplied as Lookup parameters. I installed the workflow assembly, created a case with attachments and an email. I then used the workflow design to create a new workflow with one step that runs my custom activity. The attachments copied nicely.I have created a custom workflow activity that