I too have used the Crystal OCX with VB6. Not sure about all the differences with the RDC. Here's how it works with the OCX
Add a Crystal Report (CrystalReport1) control to your form.
With CrystalReport1
.Connect = "DSN=REPORT;UID=Jack;PWD=1Fju5j9;DSQ=YOURDB"
.SelectionFormula = ""
'Reset all formulas
.Formulas(0) = ""
.Formulas(1) = ""
.Formulas(2) = ""
.Formulas(3) = ""
.Formulas(4) = ""
.Formulas(5) = ""
'Define parameters for your report formulas
.Formulas(0) = _
"StartDate= Date (" & Format(dtpBDate, "yyyy"

_
& "," & Format(dtpBDate, "mm"

_
& "," & Format(dtpBDate, "dd"

& "

"
.Formulas(1) = _
"EndDate= Date (" & Format(dtpEDate, "yyyy"

_
& "," & Format(dtpEDate, "mm"

_
& "," & Format(dtpEDate, "dd"

& "

"
.Formulas(2) = "Line= " & mintLine & ""
.Formulas(3) = "Shift= '" & mstrShift & "'"
.Formulas(4) = "DTType= '" & mstrType & "'"
.Formulas(5) = "WorkOrder= '" & mstrWorkOrder & "'"
.ReportFileName = strReportFile
.WindowTitle = strReportDesc
End With
A good getting started resource for Crystal/RDC resousces is
Hope this helps.