Dear Juan Bermudez,
It is quite easy to create a SEED dataless with Portable Data Collector Center (PDCC) when you have a combination of both a seismic sensor and digitizer (digitizer and datalogger) that PDCC contains into its library.
You can download PDCC from this web site as well as its manual in order to learn to use it:
http://www.iris.edu/manuals/pdcc_intro.htm
To have PDCC working properly, you only need to install Java Virtual Machine: that means that PDCC runs in any OS.
Once you have the dataless, you can use ObsPy library obspy.xseed to handle you SEED dataless and write a the RESP file. Please follow the next link:
http://docs.obspy.org/packages/obspy.xseed.html
Another option to extract RESP file from a SEED dataless is using RDSEED. The next command line is executed to obtain the RESP file from your dataless:
rdseed -R -f my_seed_dataless
The output RESP file will have the standard filename, RESP.GT.LPAZ.00.BHZ
I hope this will be useful.
Kind regards,
Billy Edson Burgoa Rosso