UWI format and branches, attributes

I have a verilog-AMS model and I keep getting the following error when
using AMS with Spectre:

Error found by spectre at time = 0 s during transient analysis `tran'.
UWI supports only real waveforms.
UWI supports only real waveforms.
Error detected in writing data to file `tran.tran'.

I am running with saveahdlvars set to "all". Through trial and error,
I've found that if I remove the named branches from my Verillog-AMS
file, the simulator runs.

I'd like to keep the named branches in, as it's more readable. In
fact, I'd much prefer setting saveahdlvars to "selected" and select
only the Verilog-AMS variables I'm interested in. However, I don't see
an cadence in Analog Artist to do so.

Can anyone point me to a method to either select a different output
waveform format (that doesn't use UWI) or to save only selected AHDL
variables?

 

I spoke too soon. It turns out that the UWI complaint was due to a
string parameter that the cell inherited from a different view. Named
branches work fine with UWI.