spectre: Parameters in .Alter Statement Not effecting Digital Vector File Stimuli

Hallo guys,

i've a common netlist (see below). It uses .ALTER (spice) statement and digital vector file input (stimuli). This is because alter or altergroup in spectre syntax does not work anyway.

 <<<<<<<<<<<<<

simulator lang=spectre
  finalTimeOP info what=oppoint where=rawfile
  modelParameter info what=models where=rawfile
  element info what=inst where=rawfile
  outputParameter info what=output where=rawfile
  designParamVals info what=parameters where=rawfile
  primitives info what=primitives where=rawfile
  subckts info what=subckts where=rawfile
  saveOptions options save=allpub

vec_include "../circuit_stimuli/Stimuli_102.vec" hlcheck=0

*Input Stimuli-File
parameters Supply_vec=5 \
            slope_vec=0.05 \
             zero_vec=0 \
              vth_vec=2.5

 *Main Netlist
X1 (vecIN1 vecIN2 QN VDD GND) NAND2X1
Cload (QN0 0) capacitor c=1e-12

GND_source (GND 0) vsource dc=0 type=dc
VDD_source (VDD 0) vsource dc=5 type=dc

*Analysis
tran0 tran stop=1us

simulator lang=spice

.ALTER myalt
  .param slope_vec=0.01
.END

<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

The parameters below "Input Stimuli File" are used in the *.vec file. The first (initial ones) are working fine. Now, the alter Statement changes these design variables correctly. However it seems to have no effect on the generated stimuli for the next run. Is there a way to tell spectre to "regenerate stimuli" after design Variables are changed? Or how should I rewrite it?

I got one situation in which it runs correctly, so there is a solution out there. Now i try to reveal it again.

Thanks for your help in advance.

 Regards Eberhard