Post to Post

This is a challenge, and a 307 return code addresses this:

• RFC 7231 6.4

but there seems to be some debate about whether all (modern) browsers support it. This is the correct way to do what you need. However, if you're not comfortable with it, here is a previous DevCentral Question that addresses your question:

• https://devcentral.f5.com/questions/how-to-preserve-data-in-a-http-302-redirect-of-a-post