Problems with attachments over 2MB

Hello, I've been having trouble attaching any file over 2048KB to an outgoing message. I get no error message either on the RC interface, nor the RC error log or apache logs. When I browse, then hit upload for the attachment, It goes through the upload process, but no file appears in the list of attachments.

I've verified the standard problems: php.ini max_execution_time = 300 max_input_time = 300 memory_limit = 72M post_max_size = 64M upload_max_filesize = 60M

Apache http.conf: There are no LimitRequestBody or any other LimitRequest fields in the configuration.

Am I missing some configuration element somewhere?

Thanks for your help