[TYPO3-english] Integer value from Templavoila FCE form

[ktt]

I succesfully pass string values from FCE form
to FCE's Typoscript:

temp.mytitle=TEXT
temp.mytitle.field=field_mytitle_first_part

But it doesn't work with digits:

temp.mydigit=INT
temp.mydigit.field=field_digits

My form:
 
<type>input</type>
<size>10</size>
<checkbox></checkbox>
<eval>trim</eval>

Are there any special requirements to pass integer values?

Thank you in advance,
Kast A.