[R] Time Zone query

[Neotropical bat risk assessments]

I am working with time-date data to plot temporal activity.

I would like to create a "template" to repeat the date and time for 
all potential data sets that may have differing time zone origins.

  Reading the > ?strptime help section I note that time zone is a 
variable to add.
Looking at the output of a sample data set
   Species Location    Date Time
1 Sppaaa    One 1/13/2009 17:00
2 Sppaaa    One 1/13/2009 18:00
3 Sppaaa    One 1/13/2009 19:00
4 Sppaaa    One 1/13/2009 20:00
5 Sppaaa    One 1/13/2009 21:00...

in order to understand how R is handling this and using:

 > All$Time <- as.POSIXct(strptime(as.character(d$Time), "%H:%M"))
 > All$Time
  [1] "2009-03-14 17:00:00 CST" "2009-03-14 18:00:00 CST"
  [3] "2009-03-14 19:00:00 CST" "2009-03-14 20:00:00 CST"
  [5] "2009-03-14 21:00:00 CST" "2009-03-14 22:00:00 CST"

It appears that the default is using CST and this is I assume based 
on my system setting for my PC time.
Is there a way to NOT have it do this as the data I am processing are 
from a different time zone.

Tnx

Bruce