f5 LB iRule Redirection for POST method

In RFC 7231:

6.4.7. 307 Temporary Redirect

The 307 (Temporary Redirect) status code indicates that the target resource resides temporarily under a different URI and the user agent MUST NOT change the request method if it performs an automatic redirection to that URI. Since the redirection can change over time, the client ought to continue using the original effective request URI for future requests.

The server SHOULD generate a Location header field in the response containing a URI reference for the different URI. The user agent MAY use the Location field value for automatic redirection. The server's response payload usually contains a short hypertext note with a hyperlink to the different URI(s).

  Note: This status code is similar to 302 (Found), except that it
  does not allow changing the request method from POST to GET.  This
  specification defines no equivalent counterpart for 301 (Moved
  Permanently) ([RFC7238], however, defines the status code 308
  (Permanent Redirect) for this purpose).

So the 307 may be the right code to return.

Look at soapui tool support of 307 redirect.

In your code, line 2 may be splitted before switch command. I guess this is a formatting issue when you post the code!