Remove "line breaks" from information added into HTTP header

Hi all, I use iRule to extract info about client SSL certificate and add it into HTTP header sent to server. I had to update it a bit because info about SSL certificate was not in PEM format.

Now it looks like this:

when CLIENTSSL_CLIENTCERT {
  log local0.info "SSL cert count: [SSL::cert count]"
  log local0.info "SSL cert used: [SSL::cert 0]"
  set cert [SSL::cert 0]
  set cert_whole [X509::whole $cert]
  set subject [X509::subject $cert]
  set issuer [X509::issuer $cert]
  set nva [X509::not_valid_after $cert]
  set sn [X509::serial_number $cert]
  set chash [X509::hash $cert]
  set nvb [X509::not_valid_before $cert]
  session add uie [SSL::sessionid] [list $cert_whole $subject $issuer $nva $sn $chash $nvb] 1800
}

when HTTP_REQUEST {
  log local0.info "session lookup: [session lookup uie [SSL::sessionid]]"
  if { [SSL::cert count] < 1 } {
    SSL::authenticate once
    SSL::authenticate depth 9
    SSL::cert mode request
    SSL::renegotiate
  } else {
    set values [session lookup uie [SSL::sessionid] ]
    if { [lindex $values 0] != "" } {
      HTTP::header insert Client-Auth "Valid cert"
      log local0. "Inserting Client-Auth Valid cert"

      HTTP::header insert X-SSL-DN [lindex $values 1]
      log local0. "Inserting X-SSL-DN [lindex $values 1]"

      HTTP::header insert X-SSL-Issuer [lindex $values 2]
      log local0. "Inserting X-SSL-Issuer [lindex $values 2]"

      HTTP::header insert X-SSL-Hash [lindex $values 5]
      log local0. "Inserting X-SSL-Hash [lindex $values 5]"

      HTTP::header insert X-SSL-Not-Before [lindex $values 6]
      log local0. "Inserting X-SSL-Not-Before [lindex $values 6]"

      HTTP::header insert X-SSL-Not-After [lindex $values 3]
      log local0. "Inserting X-SSL-Not-After [lindex $values 3]"

      HTTP::header insert X-SSL-SN [lindex $values 4]
      log local0. "Inserting X-SSL-SN [lindex $values 4]"

      HTTP::header insert X-SSL-Certificate [lindex $values 0]
      log local0. "Inserting X-SSL-Certificate [lindex $values 0]"
    }
  }
}

Problem is with whole PEM certificate added into HTTP header, it is stored with linebreaks (like standard cert in PEM format you receive from CA), but I need it to be in one line only. Do you know about any way how to remove all line breaks from SSL cert in PEM code?

Thanks, Zdenek