Unable to store value from Rcustom header on REFER message for Extracting it in INVITE to referred

I have to come up with a HMR which will retrieve the values from a custom header in REFER and add a new custom header to INVITE to the REFER-To party. i am trying to add these custome headers first to REFER-TO heder which will be used for INVITE RURI and then retrieving it from INVITE RURI to add the same before INVITE is sent out as out manipulation . I am able add one custom header using the HMR but unable to add the other one as the value is not stored correctly. Can someone please chck why my