Convert "hex string" to hex

I have a vi reading in from a VISA Read a string of the format;

AAAA,BBB,CC,DDD,EEE,FF,GGGGG CRLF

The 'FF' should be a hexadecimal value, but when read in it is in string format.  A simple string conversion to hex (using 'hex_bin_oct_string_conversions_LV85.vi', for example) does not work, as that results in an incorrect hex value.  For example, 'FF' might equal 00.  When 00 is converted with the string conversion to hex, the result is 3030.  I need to convert the string '00' to a hex value of 00. 

Any thoughts would be greatly appreciated.