DSP builder signaltap with derived_clock acquisition

Sir,

I have trouble in signaltap data acquisition using derived clock. Problem here is 10Hz to be displayed in signaltap with 8k sample depth, but using base clock of 50Mhz seems to be impossible. I feel the derived_clock is the only option but derived_clock assigning to signal tap keeps hanging while acquiring signaltap. How do I assign derived_clock to signaltap? Pin assignment is not clear to me and Derived_clock as trigger for segmented. Please help...

Thanks