Problem with overlay

Hi I have a requiremnet wherein the user enters data from the footer record format, and this gets written in the subfile above the footer - Check Attachment(Existing) Whenevr the user enters data in the footer, after all validations it is written to the subfileSince i also have to perform validations for headermy condition was as follows(i.e perform Header fields are only validated while writing a new record) While writing a new record(Header )Check if all the header fields are validIf not valid i.e. error in HeaderWrite SFLCTLWrite FooterElseWrite SFLCTLExfmt FooterEndifIf Error in headerRead SFLCTLRead FooterEndifEverything was working fine, until now, when the requirement has changed and the fields in the Header(Subfile Control) are also updateable. Now i am finding difficulty to toggle beween reading the subfile control and the footer to perform validationsI was wondering if the following is possible i.e. have the Header fields also in the Footer Record formatCan this be managed by OVERLAY? i.e. is it possible to display the subfile in this manner Check attachment(Is this possible) Thanks in advance for all your suggestionsDerek