Help with projection

[Luis Trevi ño]

Hi list,

some questions:

I´m building an aplication that draws some GPS points over a map. this
point are beeing updated on a postgis table. My data source is a shape
file, this data needs to be adjusted about 180 meters on the latitude
values (the data source was made with proj=utm and datum=NAD27).

I've tried using diferent input projections in order to see if mapserver
can adjust this data but I can´t get good results.

My output projection is:
 PROJECTION
   "proj=utm"
   "ellps=WGS84"
   "datum=WGS84"
 END

Could some projection help to adjust this 180 meters on the latitud?
If I transfer my shape data to postgis using a specific SRID, would help?
How can I build a specific SRID?

regards,
Luis