IRule to remove all headers with the same base name

[root@ve10:Active] config  b virtual bar list
virtual bar {
   snat automap
   pool foo
   destination 172.28.19.252:80
   ip protocol 6
   rules myrule
   profiles {
      http {}
      tcp {}
   }
}
[root@ve10:Active] config  b pool foo list
pool foo {
   members 200.200.200.101:80 {}
}
[root@ve10:Active] config  b rule myrule list
rule myrule {
   when HTTP_REQUEST {
  foreach aheader [HTTP::header names] {
    if { $aheader starts_with "iv-creds" } {
      HTTP::header remove $aheader
    }
  }
}
}

[root@ve10:Active] config  ssldump -Aed -nni 0.0 port 80
New TCP connection 1: 172.28.19.251(42603) <-> 172.28.19.252(80)
1362699807.7819 (0.0007)  C>S
---------------------------------------------------------------
HEAD / HTTP/1.1
User-Agent: curl/7.15.5 (i686-redhat-linux-gnu) libcurl/7.15.5 OpenSSL/0.9.8b zlib/1.2.3 libidn/0.6.5
Host: 172.28.19.252
Accept: */*
something: aaa
iv-creds: 111
iv-creds-1: 222
somethingelse: 333

---------------------------------------------------------------

New TCP connection 2: 200.200.200.10(42603) <-> 200.200.200.101(80)
1362699807.7829 (0.0006)  C>S
---------------------------------------------------------------
HEAD / HTTP/1.1
User-Agent: curl/7.15.5 (i686-redhat-linux-gnu) libcurl/7.15.5 OpenSSL/0.9.8b zlib/1.2.3 libidn/0.6.5
Host: 172.28.19.252
Accept: */*
something: aaa
somethingelse: 333

---------------------------------------------------------------