Modify *xls DDE link with a binary editor

[paolfili]

Hello.
I' ve an excel file with some cell connected with DDE links: i.e.
=TOS|IMPL_VOL!'.AAPL110826C335'

Using a binary editor is possible to change the cell string (AAPL->GOOG) to
obtain =TOS|IMPL_VOL!'.GOOG110826C335' ?

I' ve tried, but the result is a mess.
I suppose it' s necessary to modify some other structures.
Is there any way (exe,macros,ect) to obtain the string changes I have asked?

Thanks

Paolo