_timestamp path in ES 2.2

I am upgrading from ES 1.7 to ES 2.2 and the _timestamp deprecation broke what I was using it for.

My 1.7 mapping looks like:

"doctype": {
"_timestamp": {
"enabled": "true",
"format": "MM/dd/yyyy HH:mm:ss",
"path": "access_time"
"properties": {
"access_time": {
"format": "MM/dd/yyyy HH:mm:ss",
"type": "date"

I did this because I am using bulk_inserts and need a timestamp to pick in Kibana that is universally in all doc_types to see all the data in my index patter, but the timestamps are different for each doc_type.

Due to the 2.2 deprecation of _timestamp being limited to enabling the field, setting format and default value, this breaks my mapping. I could enable the _timestamp field and just have it be the index time; that would work, but wouldn't be ideal. The deprecation notes say to use "date", but it doesn't look like I can use "path" with "date".

Any ideas?