Connecting To Online Database Using Local Enterprise Manager

I have Enterprise Manager on my local machine. For the last twelve
months it has been connecting without problem to my online SQL Server
database provided by my ISP.

Three weeks ago the ISP applied some sort of extra security
arrangements to their SQL Server to allow access only through port
1433. they have told me to configure an alias using Network Client and
to register this alias in the usual way using my Enterprise Manager.

My problem is that despite creating the alias in exactly the way
instructed I just cannot connect to online database. I keep getting
the SQL Server does not exist or access denied when I try to connect.

As a result of advice obtained I have tried using the lite version of
the 'littleADmin' tool available from
http://www.mylittletools.net/scripts/en/mla_sql/

Using this useful looking software I find I cannot connect to the
online SQL database when it is installed on my own local machine but
if I install it on my website it does connect without problem to my
online SQL. Server database

However I need to use my more powerful Enterprise Manager to connect,
my question (at last!) is:

1. Is there likely to be a problem trying to connect to my online
database from Enterprise Manager on my local machine as a result of
the new security arrangements. In other words, is there something
analagous to what is happening with the 'littleAdmin tool' whereby
using Enterprise Manager I cannot connect from my local machine for
some reason obvious to everyone except myself??
or
2. Is it possible that there is some problem arising from Net Client?
(the aliases appear in Enterprise Manager OK)

I know my ISP should be answering this sort of question but they just
don't seem to know. I need to connect even if only to download my
database and take it to another ISP,

Best wishes, John Morgan