[amibroker] Is there a simple way to add a "timespan" to a datetime value

[tiedemj]

The new dateTimeDiff() function is great - saves a lot of date/time arithmetic. 
But is there a simple way to add a timespan (say number of seconds) to a 
dateTime value. For instance, I want to use the GTD (Good To Date) TimeInForce 
value in IBController. So what I need is something like:

TimeInForceDateTime = Now(5) + 10*60; // = now+10 minutes....

Best regards
Jens