Hi,
in v.10 the only way you have to apply spatially-variable pressure load is via APDL in a Commands snippet:
/PREP7
CSYS,nn
SFGRAD,PRES,nn,z,0_location,grad_slope
NSEL,s,...
SF,all,PRES,0 (or add a constant part to the gradient)
allsel
SFGRAD,PRES,0,z,0,0 (resets the gradient)
/SOLU
You can make it easier to select the loaded nodes if you previously make a Named Selection with Area scope: say it is named "A_P", you just call the command:
CMSEL,s,A_P
and all the nodes of this area(s) are selected.
Regards