You can e-mail Speer and they'll be able to provide data if it exists, they have for me in the past.
Other wise, you can safely use other JHP data for the same weight bullet. Sierra JHP data for their 150 gr. JHP is 6.4 - 8.0 grs.. You could comfortably use that start charge of 6.4 grs., and then work up until you are satisfied with accuracy and velocity. Keep in mind that the Sierra data is based on a 150 gr. JHP, not 155 gr., so you might not want to take it all the way up to max. I have used data for bullets that were close in weight numerous times in the past when I couldn't find data specific to a particular jacketed bullet, without any problems. You just don't want to stray too far from the target weight, and in this case we are only talking about a 5 gr. variance, which is considered close enough to be a match for the .40 cal..
GS