According to the docs, the timer start event accepts
But actually using this results in a parsing error (see below) because the seconds are missing. The ISO-8601 spec allows the seconds to be left out:
It is also acceptable to omit lower order time elements for reduced accuracy: [hh]:[mm], [hh][mm] and [hh] are all used.
and the BPMN2 spec says:
The return type of the attribute timeCycle MUST conform to the ISO-8601 format for recurring time interval representations.
The XMLGregorianCalendarImpl however does not (the xsd spec for date/time does not) ... So either the docs should be changed and note that there is a limitation, or the DurationHelper should be changed to accept without spaces.
There are other issues as well... <timeCycle>R4/2011-03-11T121300/PT5M</timeCycle> (no : between time parts) is allowed as well according to ISO8601