Miva Merchant: Save Last 4 Digits of Credit Card
<mvt:assign name="g.cc_num_clean" value="trim(glosub( glosub(g.GLOBAL_CC_NUM_VAR,'-',''), ' ', ''))" />
<mvt:assign name="g.cc_last_4" value="substring(g.cc_num_clean,len(g.cc_num_clean) - 3,4)" />
<mvt:item name="customfields" param="Write_Order(l.settings:order:id,'cc_last_4', g.cc_last_4)" />