I want to show Approval History related list to customer portal user. How can I do that?
According to this knowledge article:
you can add the approval history related list to the page layout, but when I've done this it hasn't had any effect. Regardless of how I configure my approval process, or if I (even to the point of naming the submitters as customer portal users) I can't get it to appear. This fits with the information in the 'Understanding User License Types' which shows approvals only being available for partner portal license types:
I then tried creating a visualforce page backed by a standard controller that accessed the ProcessSteps relationship of the record, but this put out no values even though I could see them in the schema browser, which indicates again that the license type precludes access to this data.
I did get something working using an extension controller that extracted the ProcessSteps related records, converted them to a custom class and then using those class instances on a Visualforce page embedded into the portal page layout. I've never used this in production though as it feels like I'm breaching the spirit, if not the letter of the license agreement.