It is not possible to set the precision of the shapes when loading a shape file from ArcView. ArcView automatically calculates the greatest precision that SDE allows based on the SDESColumn settings.
If you want to control this, you need to load the layer using the SDE Administration tools. There is a utility provided with the server for loading shape files called shp2sde. The SCALE parameter is required by the utility and sets the precision at which coordinates are stored. See SDE's on-line help for more info.