Answer
ArcPad 7.0 uses a revised projection engine. ArcGIS projection information, including datum transformations, is now embedded in ArcPad.
In versions prior to 7.0, all datum transformation parameters were specified from datum to WGS84. ArcPad 7.0 specifies all datum transformation parameters between two datums; this is the same as ArcGIS.
Reproject data using the Reproject Shapefile tool in Tools > Utilities.