Well the Blackberry Internet Service (BIS) user guide at http://docs.blackberry.com/en/smartphone_users/subcategories/?userType=1&category=BlackBerry%20Inter... details the wireless reconciliation process.

http://www.blackberry.com/btsc/search.do?cmd=displayKC&docType=kc&externalId=KB05133&sliceId=1&docTy... 0 185584215

also for Blackberry Internet Service

Reconciliation from BlackBerry smartphone to mailbox

says POP3 wireless delete is supported.

Reconciliation from mailbox to BlackBerry smartphone

table says POP3 wireless deletion is supported 

I can delete from phone to mailbox; I cannot delete from mailbox to smartphone.