How to Pass a String Design Parameter to a Cell

Hi, 

I am trying to pass a string design parameter, defined in ADE, to a cell in my schematic.  In my particular case, I have a verilog-A cell, which is a custom digital source, that uses a parameterized input waveform file.  The verilog-A code and CDF define this parameter (fname) as a string (path+filename of the playback file). If I set the cell's fname parameter to a fixed string like "/simulation/tmckeen/prbs_HV_driver_32x.txt", everything works great. 

However, when I define an ADE design variable called srcfname = "/simulation/tmckeen/prbs_HV_driver_32x.txt" and the set the cell parameter to srcfname, I get an error.  Why the error occurs can be seen in the netlist file below.  The srcfname design parameter is correct, but the instantiated cell U0 uses quotes around the fname parameter.  Somehow, I need to remove these quotes.

I thought there might be something like VAR("fname") that needs to be used in the cell parameter so the fname is evaluated before passing it to the verilog-A code.

parameters fsdiv2=1 fb=53.125G osr=32 CPW=60f \
spname="/home/user/mysync/cadence_PDK/Keystone/rfic_data/Tx/TOSA/Foton_EML_DE_022.s9p" \
srcfname="/simulation/tmckeen/prbs_HV_driver_32x.txt" fs=osr*fb Tb=1/fb \
Tsim=20*Tb Ts=1/fs

U0 (net7\<0\> net7\<1\> net7\<2\> net7\<3\> net7\<4\> net7\<5\> net7\<6\> \
net7\<7\> net7\<8\> net7\<9\> net7\<10\> net7\<11\> net7\<12\> \
net7\<13\> net7\<14\> net7\<15\> net7\<16\> net7\<17\> net7\<18\> \
net7\<19\> net7\<20\> net7\<21\> net7\<22\> net7\<23\> net7\<24\> \
net7\<25\> net7\<26\> net7\<27\> net7\<28\> net7\<29\> net7\<30\> \
net7\<31\> net7\<32\> net6\<0\> net6\<1\> net6\<2\> net6\<3\> \
net6\<4\> net6\<5\> net6\<6\> net6\<7\> net6\<8\> net6\<9\> \
net6\<10\> net6\<11\> net6\<12\> net6\<13\> net6\<14\> net6\<15\> \
net6\<16\> net6\<17\> net6\<18\> net6\<19\> net6\<20\> net6\<21\> \
net6\<22\> net6\<23\> net6\<24\> net6\<25\> net6\<26\> net6\<27\> \
net6\<28\> net6\<29\> net6\<30\> net6\<31\> net6\<32\> net1 0) \
key_dac_rdriver_osr baud=fb Rs=50 osr=osr fname="srcfname" \
cycle=1

Thanks

Trent