Incremental load, with seperate lastdate and lasttime fields

[#1]

Howdy, i'm having trouble building my incremental data load because my "last modification field" is actually a seperate date and time field..

LASTTIME,

LASTDATE

How do i go about handling this? It's not letting me do..

Where TIMESTAMP(LASTDATE,LASTTIME) >= #$(LastExecTime)#

and      TIMESTAMP(LASTDATE,LASTTIME) < #$(ThisExecTime)#;

[#2]

Please...any ideas?