Create a method in the form i.e. _PageEvent, code in it what You want to do when the Activate of the page occurs

After additing the page You can Use:

 thisform.my_pf1.PageCount=thisform.my_pf1.PageCount+1
 thisform.gotodetail_page = thisform.my_pf1.PageCount 
 newpage = "thisform.my_pf1.Page"+TRANSFORM(thisform.gotodetail_page) && Or retreive the name of the page some other way
 BINDEVENT(&newpage, "Activate", thisform,"_PageEvent", 0) && For last parameter read the help

Don't forget to UNBINDEVENTS() If You remove that page.