What database browser can we use with HSQL-mem?

I used to use a mySQL DB and its SQL browser for development and production. I wanted to give a shot at HSQL. I installed Squirrel DB Client (a free SQL browser), connected to my Grails project DB successfully according to Squirrel but I see no tables in Squirrel. The SQL log in Grails show objects being created by Hibernate:

Hibernate:
    insert
    into
        place
        (id, version, address_id, descriptor_id, primary_contact_id)
    values
        (null, ?, ?, ?, ?)

I am not sure Hibernate flushed the objects from the cache in the DB since I am using the default datasource config:

hibernate {
    cache.use_second_level_cache=true
    cache.use_query_cache=true
    cache.provider_class='com.opensymphony.oscache.hibernate.OSCacheProvider'
}

Anyone using Squirrel or another SQL db browser (free) with HSQL?

Thanks

Fred