Hi,
No mods are needed you just change the settings on the AD9517. The FMC230APP gives an example on how to do this, the fourth parameter to the application is called modeClock which can be
CLKSRC_INTERNAL_CLK_INTERNAL_REF = 0
CLKSRC_EXTERNAL_CLK = 1
CLKSRC_INTERNAL_CLK_EXTERNAL_REF = 2
Tracing modeClock variable through the program will let you know what register writes need to be done for the mode you are interested in.
We do not give out schematics. The FMC230 user manual is correct, you can use external clocking of 2.64MHz even though the datasheet says you cannot, this has been tested and we confirmed it with Analog Devices. The datasheet says that to comply with the LVPECL standard.
Regards,
Luis