Proper use of paramsaver

hi
I have a spinbox pyvcp and I would like to save and load the value every time I turn off and turn on LinuxCNC. I saw that I could do with paramsaver but I can not figure out how to use it.
some more information?
regards
Alessandro

yes
exactly where I need to put
"loadusr -W paramsaver f=NNN s=NNN b=NNN filename=xxxxxxx onstart=0/1 onexit=0/1 " ?

hi
another question:
i need to write a variable eg. #35 into pyvcp spinbox halpin vistoll
i tried with file ini mdi_command so when i push a button execute :

MDI_COMMAND = #<_hal[pyvcp.vistoll]> = #35
but it's wrong seem i read halpin but i does not write.

when i read with another button it's ok
MDI_COMMAND = #35=#<_hal[pyvcp.vistoll]>

Is there a solution ?
regards
Alessandro