Mass Cancellation of A/R Invoice, A/R Credit Memos

Hi

Is there any way for a Mass Cancellation of all open A/R Invoice, A/R Credit Memos?

Using 9.1 PL09. I tried through Open Items list but the Data > Cancel menu item is greyed out for A/R Invoices.

I also tried creating the corresponding A/R Credit Memos and A/R Invoices, but they remain unreconciled and manual reconciliation of hundreds of documents is too difficult.

Perhaps a DTW possible?

Thanks,

Ajay Audich