Help Parsing Websphere log entry

I have a websphere log entry as follows
[3/15/16 20:47:40:923 CEST] 0000005f MediationFlow E CWSXM1017E: Request flow runtime instance is unavailable due to a flow build error: 'null'.

I am able to parse the entire data using the below grok filter
grok {
match => ["message", "%{SYSLOG5424SD:EventTime} %{WORD:ErrorNumber} %{WORD:Module} (?[^*]{0,1500})"]

My problem is how to convert the retrieved time stamp because I get it as [3/15/16 20:47:40:923 CEST].

The reason I want to convert it is because I want the logstash @timestamp value to be that of the logged time of the log entry.

Please help


Something like

date {
  match => ["EventTime", "'['MM/dd/yy HH:mm:ss:SSS 'CEST]'"]

might work.

Thanks , let me the test it out and confirm