Having had a colleague told by the help desk this is impossible, it turns out they are wrong and it is possible. You override the FWD_CURVE_QUOTE_FORMAT to be RATES for absolute and POINTS as offsets.
Example code (Java):
public static void main(String [] args) throws Exception{
Session session = BlpUtil.connectToReferenceData();
Service refDataService = session.getService("//blp/refdata");
Request request = refDataService.createRequest("HistoricalDataRequest");
Element securities = request.getElement("securities");
securities.appendValue("JPY10Y CMPL Curncy");
Element fields = request.getElement("fields");
fields.appendValue("PX_LAST");
request.set("startDate", "20100527");
request.set("endDate", "20100527");
Element overrides = request.getElement("overrides");
Element override1 = overrides.appendElement();
override1.setElement("fieldId", "FWD_CURVE_QUOTE_FORMAT");
override1.setElement("value", "POINTS");
CorrelationID cid = session.sendRequest(request, null);
while (true) {
Event event = session.nextEvent();
MessageIterator msgIter = event.messageIterator();
while (msgIter.hasNext()) {
Message msg = msgIter.next();
if (msg.correlationID() == cid) {
System.out.println("msg = " + msg);
}
}
}
}