Drawing Call Flow with sequence Diagram leads to ambiguity

Question

I want to draw a Sequence Diagram Where

A -> B.run()
B.run() -> B.m1()
B.m1() -> B.m2()

So far I've come up with these.

http://i51.tinypic.com/eja5bl.jpg http://i52.tinypic.com/1449s3.jpg

But Here I cannot mention it clearly that B.m2() is called by B.m1() Rather it looks like B.run() Calls both B.m1() and B.m2() serially.

------------- EDIT ----------------

This is What I Currently have drawn http://i55.tinypic.com/21276kk.jpg

Well Is my Current Diagram Okay ?? What I want is this. (Call Flow)

SpiritAdapter -> SpiritEngine::run(spirit:string, method:string, args[])
SpiritEngine::run(spirit:string, method:string, args[]) -> SpiritEngine::executeLogic(spirit:string, method:string, args[])
SpiritEngine::executeLogic(spirit:string, method:string, args[]) -> SpiritEngine::spirit(spirit:string, method:string, args[])
SpiritEngine::spirit(spirit:string, method:string, args[]) -> new SpiritAbstractor
SpiritEngine::executeLogic(spirit:string, method:string, args[]) -> SpiritAbstractor::method(args)
SpiritEngine::run(spirit:string, method:string, args[]) -> SpiritEngine::storeXDO()

Answer 1

You can add a small bar over B.m2() and then place a self pointing arrow, for example.

Self message vs recursive call

Answer 2

The uml spec allows for a nested call to be shown visually: the called lifeline should be overlaid on the calling lifeline. See e.g. determineAvailableReport() call in this example.

Whether your tool supports it of course is another matter...

Answer 3

Lets say ObjectA has 3 methods called MessageOne(), MessageTwo() and MessageThree().

And the relation between them are shown below

void ObjectA::MessageOne()
{
    MessageTwo();
}

void ObjectA::MessageTwo()
{
   MessageThree();
}

void ObjectA::MessageThree()
{
   // TODO
}

Using Enterprise Architect as shown in the image below if you select MessageThree() call you will get an option to raise the activation level.

Once you choose that option(By clicking on -> arrow) you will get the exact diagram(Shown below) which satisfy sequence diagram of call stack.