Google is targeting its Apps BlackBerry service at businesses of all sizes with an update that it announced on Tuesday.

Google Apps Connector for BlackBerry Enterprise Server pushes Gmail and calendar items to the native client on BlackBerry phones. Companies that use it must add a piece of software to their BESes. That software connects back to Google’s mail servers, rather than an Exchange server, to synchronize mail, contacts and calendar items. It is compatible only with the Exchange version of BES.

With the new Connector for BES version 1.5, a business can support 500 BlackBerry devices per server. Previously, the service could support only half that number, even though a BES can typically handle at least 500 users, sometimes many more.

Google is also going after smaller businesses than it did previously. The updated Connector now works with BlackBerry Professional Software, which supports up to 30 BlackBerry phones.

The Connector also now works in situations where a company has a single BES that serves users in multiple Google Apps domains. That feature could help hosting companies offer the service to end-users at a lower cost, Google said in a blog post.

The updated Connector does not appear to address one particular shortcoming that the service has had since it launched. If a user makes a new calendar entry on the BlackBerry, the entry isn't synched back to their online calendar. Only the reverse synchs. At the time the Connector service launched, Google said it expected to support two-way synch by the end of this year. The company is still working on it, a spokesman said.