adjusting tap stop

Hello, I'm structuring xml and
I have an issue to make tap stop in my purpose.
I made simple list and crossreference with format <$pagenum>

for example,

<sl><sli>test<fm-xref>target<fm-xref></sli></sl>
so it shows "test 1(pagenum)"
but I want to make it "test ----------------------------1(pagenum)" for design.
Please help me about this.
Thank you.