How to Populate Values in Read-Only Fields in Create Page that are populated via WebLink?

Hi All,

We have a Requirement that Service Request needs to be created from the Opportunity Detail Page.

We have created a WebLink in Opportunity Field which opens the Service Request Create Page copying the two values of Opportunity: Opportunity ID & Opportunity Name (Short Text & Long Text Field in SR).

When we click on the Weblink and go to the Create Page of Service Request, If we make those fields Read-Only, the Values populates. But as soon as we click on Save, the value disappears.

Keeping the Two Fields Editable in the SR Create Page Works, but it exposes the Fields to be Editable by the Users, which is dangerous.