DB2 Online Restore but Without Roll Forward?
As per Information Center:


  "If this option is specified when restoring from an online backup
  image, error SQL2537N will be returned."


So you you are left with rolling forward. That being said, you could try the following

db2 rollforward db mydb to end of backup and complete


According to the information for rollforward command


  END OF BACKUP
      Specifies that all partitions in the partitioned database should be rolled forward to the minimum recovery time. See Examples section
  below for an example.


This should restore whatever it is you are attempting to restore up to the point of the end of the backup and not include any rolling forward through transactions logs that may be occurring after the backup. Normally you still have to issue at least this statement for a restore from an offline backup where you use archived logs.

I personally haven't tried nor had the need to do an online and only rollforward to the end of the backup. Give it a shot and let us all know what happens.


  EDIT: To answer your questions below: You must have archival logging
  enabled in order to take online backups. You can still take offline
  backups with archival logging. You do not have to switch back to
  circular to do so. However, once you have archival logging enabled,
  regardless of whether you are restoring from an offline or an online
  backup, you must perform a rollforward when you are done. No way
  around it. See my own previous question on this.
  
  In order to set up archival logging, you will need to alter the
  database configuration parameter LOGARCHMETH1. By default, this is
  set to OFF, which means circular logging. Your choices for it are as
  follows:
  
  
  DISK
  TSM
  USEREXIT
  VENDOR
  LOGRETAIN
  
  
  LOGRETAIN tells DB2 to leave the archived logs in the logging
  directory. It will not clean up any of these logs for you (leaving you
  as the DBA to do so). USEREXIT leaves it up to a non-IBM third party
  tool to take care of storing and archiving your logs (usually hand coded in C). Not too 
  many people use this anymore from what I understand. DISK and TSM seem
  to be used a fair amount. DISK tells DB2 where you want to archive
  your logs off to (although with a few other parameters set, DB2 can
  automatically clean up logs no longer needed-I'll show you that
  below). TSM tells DB2 to let IBM's Tivoli Storage Manager to archive
  off the logs. There are a few other settings you have to get into for
  that to work. Where I work, we haven't tried that yet.
  And lastly, VENDOR is used to use a third-party vendor product to archive off your logs.
  
  To set up archival logging of to a different disk spot and have DB2
  automatically clean things for you, you can do the following
  (NOTE:these are in Unix path)

db2 connect to mydb user &lt;admin user&gt; using &lt;admin user password&gt;
#NOTE THE double and single quotes needed on the command line in Unix
db2 "update db cfg using logarchmeth1 'DISK:/dbarch/dblogs'"
db2 update db cfg using num_db_backups 2
db2 update db cfg using rec_his_retentn 2
db2 update db cfg using auto_del_rec_obj on
db2 terminate

  
  This will tell DB2 to keep 2 full backups for at least two full days.
  Two backups have been kept for two days and another one is taken, the
  oldest backup will be deleted by DB2. DB2 will also then clean up any
  logs that were between the now deleted backup and the next oldest
  retained backup.
  
  Also note: once you switch to archival logging, DB2 will require you
  to immediately take an offline backup as your next action (ie, the
  database will be placed into BACKUP PENDING mode) and you will be
  unable to do anything else until you do so.
  
  Hope this helps!