I had a look through the driver, and it looks like it is not set up to handle the temperature and humidity stamping that you desire. The default setup string from "Default Instrument Setup.vi" is:
*ESE 60;*SRE 48;*CLS;:FORM:DATA ASC;:FORM:ELEM READ,RNUM,CHAN,TST,UNIT;:SYST:TST:TYPE RTCL;
Note: if your emoticon display settings for the LabVIEW forums are set to something other than "none" then the SCPI commands can get very emotional.
The part I bolded from determines the format of read data from page 14-53 of the user manual. To get humidity and external temperature as well, you will need to make it read something like:
*ESE 60;*SRE 48;*CLS;:FORM:DATA ASC;:FORM:ELEM READ,RNUM,CHAN,TST,UNIT,HUM,ETEM;:SYST:TST:TYPE RTCL;
Now, when you get data back, it will be in a different format, so you will need to change the "Parse Readings" VI as well. This data should be in the "remain readings" string and you just have to figure out how to extract it out into a number. The data format is shown on page 14-51 of the user manul.