External x input HPS10

Is there any point in circuit diagram of HPS10 where I can connect external horizontal X input. I woud like to use it as external unit for my spectrum analyzer (Hameg HM8028) which has X-Y output for any low frequency scope. My HPS is more then 5 year old so there is no problem with warranty. I will try it on my risk. Anyone who made any modification or experiment with this model of scope?
Thanks,
S57RZ Ljubljana
SLOVENIA

Sorry, no X-Y input or mod.