symbolics in pcells

Im building a pCell and instantiating a symbolic pTap but need to
override the default contact overlap.
I can instantiate it but cannot find a way to override the default.
Im user IC6.1.4

my Code:

;; Get the database id of the ptap symbolic
ptapId = dbOpenCellViewByType("tsmcN65" "M1_SUB" "symbolic")
;; Create a parameterized instance of it using the parameters passed
in
ptapInst=dbCreateParamInst(cv ptapId "ptapBulk" 1.6:1.4 "R0" 1
list( list("row" "float" pTapRowCnt/0.25-3 )
list("column" "float" cellWidth*2+1 )
list("xBias" "string" "center" )
list("yBias" "string" "bottom")
list("xPitch" "float" 0.25 )
list("yPitch" "float" 0.25 )
list("encByLayer1" "float" 0.2)
list("encByLayer2" "float" 0.2)
list("layer1ImpEnc" "float" 0.2)
list("layer2ImpEnc" "float" 0.2) ) )

dbClose(ptapId)

Ive dumped the contact code and here is the header:

dbiPDDCreateContact(tcCellView viaLayer layer1 layer2 encByLayer1
encByLayer2 layer1ImpLayer layer1ImpEnc layer2ImpLayer
layer2ImpEnc
w l row column xPitch yPitch xBias yBias )

I can instantiate and change the enclosue with create contact
interactively and it looks like its on
a different page:

le4ViaForm->viaSingleModeScrollView->parameters->page1->layer1EncLeft-

How can I code this into my pcell?

Thanks

Rick